Start with the category that matches the result you need: money, dates, percentages, study, health, or kitchen tasks.
New embed: Embed widget & share link builder creates prefilled share URLs and responsive iframe code. It also includes base64url cfg bundles and auto-height snippets.
Precision update: Significant Figures & Scientific Notation counts sig figs, normalizes notation, and compares textbook vs final rounding. It includes shareable How it’s calculated logs.
New optics: Lens & Mirror Equation explains 1/f = 1/dₒ + 1/dᵢ with a live step panel and ray diagram. Export CSV and share URLs for physics labs.
New electronics: RC / RL / RLC calculator covers RC/RL time constants, divider gain, and series RLC resonance. It includes full steps, CSV export, and shareable URLs.
New chemistry: Partial pressure & gas mixing covers Dalton's law, two-tank mixing, wet gas corrections, and van der Waals comparison. Export CSV and share URLs.
New chemistry: Buffer pH (Henderson-Hasselbalch) shows mole conversions, r ratios, target-pH design, and acid/base additions. It also includes buffer-capacity logs.
New worksheets: Algebra Worksheet Generator outputs deterministic seeds, worked steps, CSV export, and print-ready PDFs for algebra classes.
Graph paper: Graph paper PDF generator builds millimeter-accurate Cartesian, polar, log-log, semilog, and isometric grids with How it’s generated steps, SVG/CSV export, and shareable URLs.
Number line: Number line & interval visualizer shades inequalities, interval unions, and intersections on an SVG number line, shows step-by-step reasoning, and offers SVG/PNG, CSV, and shareable URL exports.
Dimensional analysis: Dimensional analysis & unit consistency checker expands compound units, verifies equation consistency, and builds Buckingham Π groups with shareable How it’s calculated logs.
Latest physics: Simple Harmonic Motion (SHM) simulator unifies analytic, Euler-Cromer, and RK4 solutions with a How it's calculated log, shareable URLs, plots, and CSV exports for classroom use.
Latest addition: Error propagation (with steps) brings gradient×covariance, correlation matrices, templates, and seeded Monte Carlo validation together in one multilingual workspace.
New arrival: Sampling & Bootstrap — CLT Explorer brings seeded sampling, percentile/t/normal confidence intervals, CLT histograms, CSV export, and a full How it's calculated walkthrough to one shareable workspace.
Now available: Truth Table & Logic Evaluator builds paged truth tables, canonical DNF/CNF, and Karnaugh or Quine–McCluskey simplifications with shareable URLs, CSV export, and How it’s calculated logs.
Brand-new: Probability Simulator runs reproducible coin, weighted dice, and roulette experiments with theory vs empirical comparisons, Wilson 95% intervals, convergence charts, EV/house edge, CSV/LaTeX exports, and full How it's calculated steps.
Fresh release: CI & Hypothesis Test Wizard guides one- and two-sample mean or proportion analyses with Wilson/Newcombe intervals, live p-value shading, and shareable URLs.
New release: Riemann Sums Explorer plots left/right rectangles, trapezoids, and Simpson arcs, logs every step, compares an adaptive Simpson reference integral, and exports CSV, LaTeX, and shareable URLs.
Fresh drop: Distributions Pack Calculator brings binomial, Poisson, Student’s t, and chi-square together with PMF/PDF, CDF, quantiles, exact intervals, canvas visuals, CSV, LaTeX, and share links for class transparency.
New release: First-order ODEs (separable & linear) visualises the slope field, Simpson integrals, integrating factor, numeric inversion, RK4 error, CSV export, and shareable URLs in one workspace.
Check out the new Function Transformations Explorer to see how y = a·f(b(x−h)) + v shifts, scales, and reflects classic functions with step-by-step explanations.
New: Vector Calculator with step-by-step logs for dot/cross, projection, angle, areas, and the triple product, plus a 2D diagram.
Fresh release: Eigenvalues & Eigenvectors Explorer covering 2x2 and 3x3 matrices with rational-root checks, QR iteration, RREF eigenvectors, residuals, and a diagonalizability verdict.
We also launched the Limits Explorer to show numeric L'Hôpital iterations, one-sided sampling, and ready-to-share CSV logs.
Latest addition: Taylor & Maclaurin Series Explorer pairs symbolic derivatives with a least-squares fallback, plots f and P_n together, and exports error summaries, LaTeX, CSV, and shareable URLs.
New utilities: Random Number Generator, Text Case Converter, Image Resizer, Random Picker, Zenkaku / Hankaku Converter, and JSON Formatter & Validator all run entirely in the browser and are ready to embed.
Popular calculators
Quick links to commonly used calculators in English.
Favorites
Save a calculator to keep it here and on the home page.
Filter calculators
Popular searches
- Free online tools for PDF, images, text, and random tasks | CalcBE
Open browser-based tools for PDF work, image cleanup, worksheets, text formatting, and random picks.
- Annotation paper PDF generator (comment margin) | CalcBE
Create annotation paper with an adjustable comment margin and ruled, dot, or blank guides in millimeters.
- Topic hubs for calculators and tools | Find by task | CalcBE
Choose a task first, then open the topic hub that narrows calculators and tools for money, study, time.
- Base Converter & Bitwise Toolkit (Bin/Oct/Dec/Hex) | CalcBE
Convert between binary, octal, decimal, and hexadecimal, and run AND/OR/XOR/NOT and bit shifts—then copy a shareable result link.
- Acid–base pH
Solve acid–base pH for strong and weak acids and bases, plus strong acid–strong base mixtures.
- Password generator – strong secure random passwords | CalcBE
Generate strong random passwords in your browser with crypto.getRandomValues.
- A/B Test Significance Calculator | CalcBE
Check A/B test results with conversion rates, lift, z-test p-value, confidence interval, and Bayesian win probability.
- Algebra simplifier with colors for like terms | CalcBE
Expand with distribution, color-match like terms, and simplify step by step.
Recently used
Every calculator you open is remembered locally so you can jump back in quickly.
Finance & money
Plan loans, project compound growth, convert currencies, and split bills.
- Loan calculator (monthly payment, interest, payoff)
Calculate monthly loan payment, total interest, and payoff timeline from principal, APR, and term.
- Mortgage repayment planner – monthly payments, lump sums
Simulate mortgage repayments with equal payment or equal principal methods, include bonus payments, lump-sum.
- Compound Interest Calculator
Estimate future value and Effective Annual Rate from APR, compounding frequency, years, and optional monthly.
- Discount calculator – stacked percentage, amount
Enter a list price and stack percentage cuts, fixed-amount deals and coupons to see final price and savings.
- Retirement Savings Calculator
Project your retirement nest egg by combining current savings, recurring monthly contributions, investment growth.
- Fuel Economy, Gas Cost and Trip Cost Calculator
Estimate your real-world fuel economy, gas cost for a drive, and total trip cost including tolls and parking.
- APR to APY (EAR) Calculator
Use this interest rate converter to switch between APR, APY/EAR, monthly, and daily rates, or run the reverse.
- Biweekly loan amortization schedule (CSV export)
Compute a biweekly amortization schedule (26 payments/year), include extra payments, and export the table to CSV.
- Bond Duration / DV01 / Convexity Calculator
Calculate Macaulay duration, modified duration, DV01, and convexity.
- Bond Price ↔ Yield (YTM) Calculator
Compute bond price and yield to maturity (YTM) from coupon, maturity, and price or yield.
- Break-even Point and Required Sales Calculator
Calculate the break-even point, required sales to reach a target profit, and profit at your planned sales volume.
- Consumption Tax Calculator
Calculate Japanese consumption tax with standard 10%, reduced 8% or custom rates per item.
- Credit card minimum payment simulator – payoff time
Estimate months to payoff and total interest by entering balance, APR, and your card’s minimum payment policy (rate.
- Credit Card Payoff & Debt Snowball Calculator
Estimate payoff time, total interest, and compare debt snowball.
- DCF Calculator — Simple valuation with sensitivity
Estimate enterprise value from an FCF forecast with discount rate, terminal value, net debt, per-share value.
- Debt-to-income (DTI) ratio calculator
Enter monthly income and monthly debt payments to compute your DTI percentage and a quick category label.
- Deposit interest calculator: future value & EAR
Find future value, interest, and EAR from deposit amount, rate, years, and compounding choice.
- Electricity Cost Calculator
Estimate electricity use and running cost from watts, hours per day, quantity, and your own price per kWh.
- EMI calculator (loan EMI, monthly payment)
Calculate India loan EMI in INR from principal, annual interest rate, and term.
- Fee Drag Calculator – How fund fees reduce long-term returns
Compare 0% vs annual fees (expense ratio).
- Fixed Deposit (FD) calculator
Compute maturity value, interest earned, and effective annual rate (EAR) from principal, annual rate, years.
- GST Calculator (Add/Inclusive)
Enter amount and GST rate (5/12/18/28%) to compute base, GST amount, and total for both exclusive and inclusive cases.
- Income Tax Calculator India (FY example)
Estimate India income tax with educational example slabs for selected fiscal years.
- Inflation Calculator
Adjust an amount between years using U.S.
- Interest Rate Calculator (RATE) — Solve APR from Payments
Solve interest rate from loan amount, payments, and term (Excel RATE equivalent).
- Invoice net ↔ gross calculator for VAT checks
Convert invoice amounts between net and VAT-inclusive totals.
- Lira ↔ kurus converter – Turkish currency units
Convert between Turkish lira and kurus with live calculations that respect 100 kurus = 1 lira.
- Live FX currency converter – ECB reference rates
Convert currencies with live FX rates from ECB or Open ER API, view recent history, and share results.
- Loan affordability calculator – max payment (DTI)
Estimate the maximum monthly payment (EMI) and loan amount from monthly income, EMI ratio (DTI), APR, and term.
- Loan amortization schedule (with CSV export)
Build an amortization schedule with principal, interest, and balance per payment.
- Margin & markup calculator – profit margin, markup
Enter cost, price, margin %, or markup % and instantly solve the remaining fields.
- Mortgage and Loan Repayment Burden Checker
Check your debt-to-income (DTI) ratio for a planned mortgage and other loans, and estimate how much you can safely.
- Mortgage Rate Increase Simulator — Payment and interest impact
Simulate mortgage rate increase scenarios and compare payments vs a fixed-rate baseline.
- Net ↔ gross salary converter – illustrative tax
Quickly convert between gross and net salary using a simple example tax rate.
- New NISA savings simulator – allowance vs taxable
Project New NISA contributions versus a taxable account, track annual and lifetime allowance usage, and compare.
- NPV Profile Calculator – Discount Rate Sensitivity & IRR
Generate an NPV profile by sweeping discount rates.
- Payback period calculator – simple & discounted payback
Compute simple and discounted payback from initial investment and periodic cash flows.
- Portfolio Rebalance Calculator
Compute buy/sell amounts from current holdings and target weights.
- PPF Calculator (Annual Contribution — Educational)
Estimate maturity, total invested, and gain from annual contribution, APR, and years with a simple annual-compounding.
- Price, Cost, Margin and Markup Calculator
Quickly calculate profit margin, markup, selling price and cost per unit.
- Recurring Deposit (RD) Calculator
Compute maturity amount, total invested, and estimated gain from monthly deposits, annual rate, and years.
- Refinance break-even calculator – when closing costs pay off
Compare current and refinanced loans.
- Rent vs Buy Calculator (Break-even with Costs & Investing)
Compare renting vs buying with mortgage, taxes, maintenance, selling costs, and investment opportunity cost.
- ROI & CAGR Calculator
Calculate ROI, CAGR, gain or loss, and value multiple from an initial value and a final value.
- Salary gross ↔ net educational estimator – taxes
Convert gross ↔ net salary using simple flat or example progressive rates.
- Savings Goal & Monthly Contribution Calculator
Work out the monthly contribution to hit a savings goal, project how far deposits grow, or estimate the time needed.
- Savings Goal Planner: Deposits, Time, Future Value
Work out the deposit needed to hit a savings target, the time required at a chosen deposit, or the future value.
- Simple & Compound Interest, NPV & IRR Calculator
Compare simple and compound present/future values alongside cash-flow NPV and IRR.
- SIP Calculator for Monthly Investment
Estimate SIP maturity amount, total invested, and expected gain from monthly investment, annual return, years.
- Split Bill Calculator (tax, weights, rounding, QR)
Split a bill with inclusive or exclusive tax, custom weights, representative adjustments, and share the result.
- Tip & split calculator – restaurant tip, bill sharing
Enter the bill total and tip percentage to instantly see the tip amount, new total, and per-person share.
- TVM Solver (PV/FV/PMT/NPER/RATE) — Loan & Investment
Solve PV, FV, PMT, NPER, and RATE in one place for loans or investments.
- VAT / Sales Tax calculator – exclusive ↔ inclusive
Convert between net and gross amounts for VAT or sales tax.
- VAT net ↔ gross quick converter – add VAT to net
Quickly convert between VAT-exclusive (net) and VAT-inclusive (gross) prices at standard rates.
- Withdrawal Simulator — How long your portfolio lasts
Simulate portfolio withdrawals with inflation adjustment and a max-withdrawal solver.
- XIRR Calculator (Irregular Cash Flows) – Paste CSV
Calculate XIRR from irregular dated cash flows online.
- XNPV Calculator (Dated NPV for Irregular Cash Flows)
Calculate XNPV for irregular dated cash flows online.
Unit converters
Convert everyday units quickly for study, travel, and DIY projects.
- Universal Unit Converter for Length, Area, Volume & More
Convert length, area, volume, mass, speed and temperature units instantly.
- Temperature Converter (Celsius, Fahrenheit, Kelvin)
Convert between Celsius (°C), Fahrenheit (°F), and Kelvin (K) with precise formulas, keyboard input.
- Length Converter (m, km, cm, mm, inch, foot, yard, mile)
Convert lengths across metric and imperial units at once with SI‑based factors, keyboard input, and a shareable.
- Currency converter – manual rates, base currency
Convert currencies with manual rates or a base‑currency cross.
- Data Transfer Time Calculator (Size, Speed, Time)
Calculate transfer time, required speed, or transferable data size with bit/byte and SI/IEC unit conversion.
- Air Conditioner Size Calculator
Estimate room AC capacity from floor area or room dimensions.
- Dimensional Weight Calculator
Calculate parcel volume, dimensional weight, and chargeable shipping weight.
- PPM to Percent Converter
Convert between ppm, ppb, ppt, percent, per-mille, mg/kg, and mg/L (water).
- Screen Size Calculator
Convert screen diagonal into real width and height, estimate viewing distance, and calculate PPI or pixel pitch.
- Video Bitrate Calculator
Use this video file size and bitrate calculator to estimate file size, required video bitrate, or recording time.
Date & time
Track schedules, deadlines, and logs with dedicated date-time tools.
- Date Difference Calculator (days, business days, Y/M/D)
Compute days between dates, count business days and working hours, and see a year‑month‑day breakdown.
- Business Days & Countdown Calculator
Count calendar or business days between two dates, exclude custom weekend patterns and holiday lists, and jump forward.
- Time Zone Converter (Instant World Clock)
Enter a date and time to convert between time zones, with automatic daylight‑saving shifts, presets for major cities.
- Hours & Minutes Time Calculator
Add or subtract HH:MM and HH:MM:SS durations for work shifts, breaks, overtime, and task totals.
- Age Calculator
Calculate exact age from date of birth in years, months and days.
- Speed–Distance–Time Calculator with Pace & ETA
Calculate speed, distance, or time from the other two.
- Age Difference Calculator
Enter two birth dates to calculate the exact age difference in years, months, weeks and days.
- Best Meeting Time Across Time Zones
Find the best meeting time across time zones using working-hour overlap, ranked suggestions, and a shareable.
- Birth Year Calculator
Estimate possible birth years from age and a reference date.
- Days Until Calculator
Count how many days until any date or event.
- Event Countdown (Time Remaining)
Show time remaining until a target date/time with an analog + digital display.
- Fiscal Week, Week Number & Quarter Calculator
Find fiscal week, ISO week, calendar quarter, fiscal quarter, and fiscal year for any date.
- Meeting Time Overlap Finder
Find overlapping meeting windows across two to four cities, compare local times, and share the best candidate slot.
- Military Time Converter: 24 Hour to 12 Hour, AM/PM
Convert military time to AM/PM and AM/PM to 24-hour time instantly.
- Recurring counter: counts in range, next date, Nth
Count how many times a recurring event happens in a date range.
- Work Hours & Overtime Pay
Estimate worked time, overtime hours, and gross pay from shift start/end times, unpaid breaks, or known total hours.
- World Clock Board (Multiple Time Zones)
Compare multiple city times with analog + digital clocks, work-hour highlights, shareable URLs, and JSON.
Math & statistics
Solve common classroom and analytics problems without spreadsheets.
- Pi Approximation Explorer
Compare polygon, Gregory, Nilakantha, and Monte Carlo approximations of pi with charts, errors, examples.
- Pi Algorithm Race
Race Gregory, Nilakantha, Machin-like, and Chudnovsky pi algorithms with fixed-time and fixed-digits modes, charts.
- Pi Digits Generator
Generate the first n digits of pi with a Chudnovsky-based browser tool.
- Pi Digit Lab
Search for a digit sequence, jump to a position, move block by block, and copy a selected range inside the first n.
- 2D graphing calculator – plot and intersect functions
Plot up to three functions, find intercepts, intersections and extrema numerically, and explore the graph with zoom.
- Quadratic & Polynomial Solver with Steps
Solve quadratic and degree-3 polynomial equations with exact and decimal roots, discriminant checks, factorization.
- Fraction Simplifier & Mixed Number Converter
Reduce any fraction, convert between improper and mixed numbers, and review Euclidean GCD steps with pie and number.
- Percentage Calculator (X% of Y, increase/decrease)
Work out X% of Y, what percent one number is of another, and the new value after a percent increase or decrease.
- Probability Simulator — coin, dice, roulette
Simulate coin tosses, dice rolls and roulette spins with a fixed seed to compare theoretical and empirical.
- Quadratic Equation Solver – Roots, Discriminant & Vertex
Solve ax² + bx + c = 0 and see real or complex roots, the discriminant, vertex form and a quick graph.
- 2-column / 3-column notes (T-chart) PDF generator
Create 2- or 3-column note paper in millimeters.
- 2D geometry calculator – area & perimeter of shapes
Compute area and perimeter for rectangles, circles, triangles, trapezoids, and regular polygons with formulas.
- 3D Geometry Calculator (Sphere, Cylinder, Cone, Prism)
Compute volume and surface area for spheres, cylinders, cones, rectangular and regular prisms—with example inputs.
- A/B Test Significance Calculator
Check A/B test results with conversion rates, lift, z-test p-value, confidence interval, and Bayesian win probability.
- A260 Calculator (DNA/RNA Concentration & Purity)
Use A260/A280/A230 and dilution to estimate DNA/RNA concentration (ng/µL) plus A260/280 and A260/230 purity ratios.
- Accessible Color Palette Generator
Build a role-based accessible palette from one approved base color, then review surface, text, accent, and button.
- Acid-base titration curve & pH
Compute pH during acid-base titrations and generate titration curves.
- Acid-base titration curve simulator
Plot pH versus added volume for strong/weak acid-base systems, highlight key points, and export CSV or share URL.
- Acid–base pH
Solve acid–base pH for strong and weak acids and bases, plus strong acid–strong base mixtures.
- Add Page Numbers & Watermarks to PDF
Add page numbers or text watermarks to a PDF in your browser.
- Algebra simplifier with colors for like terms
Expand with distribution, color-match like terms, and simplify step by step.
- Algebra Worksheet Generator
Create printable algebra handouts with answer keys and optional worked steps.
- Angular separation and position angle calculator
Compute angular distance and Position Angle (PA) between two sky coordinates.
- Annotation paper PDF generator (comment margin)
Create annotation paper with an adjustable comment margin and ruled, dot, or blank guides in millimeters, then print.
- ANOVA Calculator
Paste grouped raw values to run a one-way ANOVA, inspect the ANOVA table, F statistic, p-value, eta-squared.
- AQI (Air Quality Index) Calculator (US EPA)
Convert 24-hour PM2.5 and PM10 concentrations (µg/m³) to US EPA AQI.
- Arithmetic & Geometric Sequence Calculator
Compute the nth term, partial sum, common difference or ratio, and number of terms for arithmetic and geometric.
- ARR NNT Calculator
Calculate absolute risk reduction, relative risk reduction, and NNT or NNH from control and experimental event rates.
- Aspect Ratio Calculator
Simplify image or video ratios, solve a missing width or height, and preview contain, cover, and crop behavior.
- Astronomy Session Planner
Plan one-night observing sessions by ranking targets with shared constraints, timeline views, and CSV/JSON export.
- Astronomy Workspace Pro
Manage observing projects in one workspace, keep shared location, date, and equipment settings while opening connected.
- Attributable Fraction Exposed Calculator
Estimate attributable fraction among exposed and attributable percent among exposed from group risk, or from direct.
- Attributable Risk Calculator
Compare exposed and unexposed groups to review attributable risk and attributable fraction together.
- Attributable Risk Percent Calculator
Estimate attributable risk percent from exposed and unexposed risk, or from a direct attributable risk.
- Balanced Accuracy Calculator
Calculate balanced accuracy, recall, specificity, precision, prevalence, and accuracy from TP, FP, TN, and FN.
- Base Converter & Bitwise Toolkit (Bin/Oct/Dec/Hex)
Convert between binary, octal, decimal, and hexadecimal, and run AND/OR/XOR/NOT and bit shifts—then copy.
- Base64 Encode / Decode Tool
Encode text to Base64, decode Base64 to text, and convert files to Base64 or data URI locally in your browser.
- Bayes Theorem Calculator
Update a prior probability with Bayes' theorem.
- Beer-Lambert law & calibration curve
Compute absorbance, concentration, molar absorptivity, path length, and calibration curves with Beer-Lambert steps.
- Bell numbers table with Stirling relations
Generate a Bell numbers table B(n) and confirm the relation B(n)=ΣS(n,k).
- Beta Distribution Generator & Visualizer
Generate random samples from a Beta distribution and visualize the PDF and histogram.
- Beta diversity calculator (Jaccard / Bray–Curtis)
Compute beta diversity between samples using Jaccard (presence/absence) or Bray–Curtis (abundance).
- Bingo card generator (printable)
Generate printable bingo cards and call lists in your browser.
- Binomial Test Calculator
Enter successes, trials, and a null proportion to read exact binomial-test p-values.
- Birthday Paradox Calculator (Collision Probability)
Calculate the birthday paradox collision probability with exact math + a Monte Carlo simulator.
- Buffer pH (Henderson-Hasselbalch)
Compute buffer pH with Henderson-Hasselbalch, design target-pH mixtures, and estimate acid/base addition effects.
- Calligraphy guide sheet PDF generator
Adjust x-height/ascender/descender ratios, slant angle (52–55°), unit lines, vertical guides, and left margin lines.
- Calorimetry calculator (specific heat, heat, final temperature)
Calculate heat, specific heat, temperature change, and final equilibrium temperature for two-substance calorimetry.
- Card deck shuffler – shuffle & draw cards
Shuffle a deck of playing cards and draw or deal cards in your browser.
- Catalan number explorer - Dyck paths & trees
Explore Catalan numbers C_n with exact BigInt or modulo tables, then enumerate or uniformly sample Dyck words, Dyck.
- Catalog Resolver Pro
Offline catalog resolver for M/NGC/IC/C IDs with filters, sorting, multi-select, CSV import, and CSV/JSON export.
- Catalyst loading (mol%, ppm, eq)
Convert catalyst loading between eq, mol% and ppm/ppb and compute mass, volume, or stock amounts from a base.
- Cell seeding calculator
Calculate required cell suspension and media volume from target cells/well (or cells/cm²), number of wells, volume.
- Centrifuge converter (rpm ↔ RCF ×g)
Convert between centrifuge speed (rpm) and relative centrifugal force (RCF, ×g) using rotor radius (mm/cm/in).
- CFU/mL Calculator
Calculate colony forming units per mL from colony count, serial dilution, and plated volume.
- Chemical Equation Balancer + Stoichiometry
Balance reactions with Gauss-Jordan steps, then compute limiting reagent, percent yield, and redox combinations.
- Chemical equilibrium ICE table (Kc/Kp)
Build ICE tables from Kc/Kp and initial conditions, solve the extent with a 5% small-x check, and share the setup.
- Chi-Square Test Calculator
Run chi-square goodness-of-fit and independence tests from observed counts.
- Chinese character grid (Tianzige / Mizhige) PDF
Generate Tianzige/Mizhige practice grids in millimeters.
- Circular & necklace permutation calculator
Compute circular permutations (rotation counted as the same) and necklace/bracelet permutations (rotation + reflection.
- Circular motion & centripetal force calculator
Calculate centripetal acceleration, force, angular speed, period, frequency, and banked-curve angle with formulas.
- Clock Tools: Meeting Planner, Unix Timestamp, Timer
Browse clock and time tools for meeting planning, Unix timestamp conversion, military time conversion, timers, alarms.
- Cohen's Kappa Calculator
Calculate Cohen's kappa from paired labels or a contingency table.
- Colligative properties (ΔTb, ΔTf, π)
Compute boiling-point elevation, freezing-point depression and osmotic pressure, or estimate molar mass.
- Color Converter
Convert one color between HEX, RGB, HSL, and a matching common color keyword.
- Color Difference Checker
Compare two colors by RGB distance and a simple perceptual ΔE76 gap, then review HEX, RGB, and HSL values in your.
- Color Harmony Generator
Generate analogous, complementary, triadic, or split-complementary color sets from one base color, then copy HEX, RGB.
- Color Mixer
Blend two colors by ratio, then inspect the mixed result in HEX, RGB, HSL, and a matching common color keyword.
- Color Palette Generator
Generate quick tints, shades, tones, and accent colors from one base color, then inspect HEX, RGB, and HSL values.
- Color Picker
Pick a color and read HEX, RGB, HSL, plus quick contrast checks against black and white.
- Color Scale Generator
Build a quick 5, 7, or 9-step color scale from one base color, preview each step, and copy HEX, RGB, or HSL values.
- Color Temperature Checker
Check whether one color reads warm, cool, or neutral, then compare a slightly warmer and cooler variation in your.
- Color Token Audit
Audit one token-ready color set before export.
- Color Token Diff
Compare two token-ready color sets role by role.
- Color Token Export Generator
Start from one approved brand color, then export light and dark role palettes as CSS variables, JSON tokens.
- Color Token Naming
Stabilize semantic, component, state, and theme token naming before audit or export.
- Color Token Preview
Preview light and dark tokenized UI cards before exporting CSS variables or JSON tokens.
- Column Arithmetic Worksheet Generator
Build printable column-arithmetic worksheets for addition, subtraction, multiplication, division, decimal.
- Compare Two PDFs – Find Text Differences in Browser
Select two PDFs, extract their text in your browser, and highlight added or removed lines or paragraphs.
- Complex Number Calculator — a+bi ↔ polar with steps
Convert between a+bi and r∠θ, perform complex addition, subtraction, multiplication, division, powers, and list n-th.
- Component Color Tokens
Turn approved role colors into component aliases such as button, card, input, nav, and badge tokens.
- Concentration & pH Calculator (Step-by-Step)
Covers molarity, mass percent, dilution, mixing, w/w→M, and strong/weak acid-base or buffer pH with 25 °C.
- Concrete, Gravel & Mulch Calculator
Estimate concrete volume and bag counts, gravel coverage and tons, and mulch bags with US or metric inputs.
- Confidence Interval & Hypothesis Test Wizard
Build confidence intervals and hypothesis tests for means and proportions with t/z workflows, Welch, paired, Wilson.
- Confusion Matrix Calculator
Calculate confusion matrix metrics for binary classification from TP, FP, TN, and FN.
- Conic sections calculator – standard form & focus
Classify a general quadratic, rotate to eliminate xy, complete the square to standard form, and visualize focus.
- Contrast Checker
Check contrast ratio for foreground and background colors, then see quick WCAG AA/AAA verdicts for normal.
- Coordinate geometry calculator – distance & lines
Compute distance, midpoint, slope, line equations, circles, and intersections with full working shown beside.
- Cornell notes PDF generator – cue/notes/summary layout
Generate Cornell notes paper as SVG in millimeters.
- Correlation Calculator
Paste XY pairs to calculate Pearson or Spearman correlation, two-sided p-value, squared coefficient, sample count.
- Coupon Collector Calculator (Expected Draws & Completion)
Solve the coupon collector problem with expected draws n·H_n, completion probability P(T≤t), and t50/t90/t99.
- Cp Cpk Calculator - Process Capability, Pp Ppk, DPMO &
Paste measurements or enter mean and SD with LSL/USL to calculate Cp, Cpk, Pp, Ppk, estimated PPM/DPMO and sigma level.
- CSS Color Mix Generator
Build a ready-to-paste CSS color-mix() string from two known colors, then preview the mixed result in OKLCH or sRGB.
- CSV Column Profiler
Paste CSV or TSV data to inspect column types, missing values, unique counts, and next chart or stats options.
- Deadline Countdown Calculator
See remaining calendar days, business days, and business hours until a deadline in one page.
- Decimal Long Division
Learn decimal long division by separating the decimal shift, the transformed equation, and the long-division steps.
- Decimal Long Multiplication
Learn decimal long multiplication by separating the whole-number multiplication from the step where the decimal point.
- Deck & Terrace Paint Area Calculator
Estimate deck and terrace paintable area plus primer/topcoat gallons or liters from one rectangle, multiple zones.
- Depth of Field Calculator
Estimate focus near limit, far limit, total depth of field, and hyperfocal distance from lens settings.
- Descriptive Statistics + Box Plot & Histogram
Paste a dataset or upload CSV/TSV to review descriptive statistics, histogram, box plot, outlier counts, trimmed mean.
- Dew Point, Wet Bulb, Heat Index & Wind Chill Calculator
Calculate dew point, wet bulb temperature, heat index, wind chill, and apparent temperature from temperature.
- DFT/WFT Calculator
Convert dry film thickness (DFT) and wet film thickness (WFT), estimate coverage and paint consumption.
- Diagnostic Odds Ratio Calculator
Calculate diagnostic odds ratio from TP, FP, TN, and FN.
- Dice stats (odds & distribution) + PNG sharing
Compute odds and distributions for NdS +/- K.
- Dice tools – roller, TRPG checks, dice stats
Browser-only dice tools: dice roller, TRPG checks, and dice stats for odds and distributions.
- Differentiation Calculator (steps, tangents, numeric)
Compute symbolic and numeric derivatives for single-variable, parametric, implicit, and partial derivatives.
- Dimensional analysis & unit consistency checker
Check unit consistency, parse compound units, and build Buckingham Pi groups with step logs and shareable results.
- Dirichlet Distribution Generator & Visualizer
Generate probability vectors from a Dirichlet distribution and visualize marginals and simplex plots.
- Distance and bearing calculator for two latitude/longitude
Calculate distance, initial bearing, and final bearing between two latitude/longitude points with WGS84 ellipsoid.
- Distance Modulus Calculator with Steps (m, M, d)
Solve the distance modulus formula m - M = 5 log10(d/10 pc) with apparent magnitude, absolute magnitude, or distance.
- Distribution Sampler and Histogram Tool
Generate random samples from common distributions, visualize histograms, review summary stats, and export CSV/JSON.
- Distributions — binomial, Poisson, t, chi square
Compute PMF or PDF, CDF, quantiles, and exact intervals for binomial, Poisson, Student t, and chi-square.
- Diversity index calculator (Shannon & Simpson)
Calculate diversity indices from category counts.
- DNA/RNA Concentration Converter
Convert DNA or RNA concentration between ng/µL, nM, and copies/µL from fragment length and type.
- DO Saturation and BOD/COD Calculator
Calculate dissolved oxygen (DO) saturation and % saturation from water temperature, salinity, and pressure, plus BOD.
- Dot grid paper PDF generator – printable SVG in mm
Generate dot grid paper as an SVG in millimeters.
- Earth Curvature and Horizon Calculator
Calculate horizon distance, earth curvature drop, hidden height, and how far you can see from observer height.
- Earthquake b-value calculator (Gutenberg-Richter)
Load an earthquake CSV or TSV catalog, build a cumulative frequency-magnitude distribution, and estimate.
- Earthquake Energy Calculator: Magnitude Comparison
Use this earthquake energy calculator to compare two magnitudes and estimate how much more energy a magnitude 7.
- Effect Size Calculator
Calculate Cohen's d, Hedges' g, or eta-squared from two-group summaries or one-way ANOVA summaries, then read.
- Effective stack height calculator (simple plume rise)
Estimate plume rise Δh and effective stack height He with a simplified Briggs method.
- Eigenvalues & Eigenvectors (2x2, 3x3) — with steps
Compute eigenvalues, eigenvectors, residuals, and multiplicities for 2x2 and 3x3 matrices with analytic.
- Electricity CO₂ emissions calc (kWh→kg-CO₂ conversion)
Estimate electricity-related CO₂ emissions from energy use and an emission factor, with conversion between kg.
- Electrochemical cell & Nernst equation
Explore standard cell potentials E°, ΔG°, K, Nernst equation E, and concentration cells with steps.
- ELISA standard curve fitter (4PL/5PL)
Fit 4PL/5PL curves to ELISA standards, estimate unknown concentrations, and review weighting, residuals.
- Empirical & molecular formula
Derive empirical and molecular formulas from composition, combustion, or hydrate data with step logs and CSV export.
- Engineering paper PDF generator
Generate engineering paper with 4/5/10 squares per inch converted to millimeters.
- Entropy and KL Divergence Calculator
Calculate entropy, cross-entropy, KL divergence, and JS divergence from probability vectors P and Q.
- Epoch Converter
Quickly parse Unix epoch seconds, milliseconds, or ISO 8601 dates into UTC and browser local time.
- Epoxy & Paint Mix Ratio Calculator (Weight or Volume)
Split two-component epoxy or paint kits by weight or volume, convert weight ratios with densities, and see Part A/B.
- Epoxy Resin Calculator – Volume, Weight & Density
Estimate epoxy volume and weight from area and thickness or mold size.
- Error Propagation Calculator with Steps
Propagate uncertainty for sums, products, powers, and custom formulas with gradient×covariance steps, correlation.
- Expected Value Simulator
Compare theoretical expected value, variance, and simulated averages for coin flips, dice, or simple lottery-style.
- Exterior Paint Calculator
Calculate exterior wall area and how much paint you need.
- F-Beta Score Calculator
Calculate F-beta from precision and recall, or from TP, FP, and FN.
- Factor Pairs Calculator
Enter a whole number to list every factor and factor pair.
- Fence Paint Calculator
Estimate fence paint from length and height, panel mix, or known area.
- Field Rotation Planner
Plan parallactic angle and field rotation rate through the night, with optional exposure limit estimate.
- Finder Chart Pro
Build finder charts from Right Ascension (RA) and Declination (Dec) with grid, scale bar, orientation markers.
- First-Order ODE Solver (Separable + Linear)
Solve separable and linear first-order ODEs with slope fields, integrating factors, Simpson integrals, numeric.
- Fisher Exact Test Calculator
Enter one 2x2 table to read Fisher exact test p-values in two-sided, greater, or less form.
- Flashcard / index card PDF generator (cut guides)
Auto-arrange 3x5, 4x6, A7, and custom index cards on one page with cut lines or crop marks, then print a precise.
- Float Inspector Tool
Inspect IEEE 754 bit layouts for float16, bfloat16, float32, and float64.
- Fraction calculator
Enter mixed or improper fractions as-is, perform addition, subtraction, multiplication, or division, and instantly.
- Free PDF Tools – Compress, Merge & Convert in Browser
Compress, merge, split, and convert PDFs free in your browser.
- Free QR code generator & scanner – create, verify
Generate QR codes for URLs, text, Wi-Fi, contacts, phone, email, and SMS.
- Friedman Test Calculator
Run a Friedman test for 3+ paired groups. Review Q, the p-value, tie correction, Kendall's W, and rank summaries.
- Fullscreen Clock
Show a large fullscreen clock in your browser with analog and digital views, seconds toggle, timezone options.
- Fullwidth/Halfwidth Katakana Converter (Zenkaku/Hankaku)
Convert Japanese text between fullwidth/halfwidth and Hiragana/Katakana in your browser.
- Function Transformations Calculator
Graph function transformations from the parent graph.
- Gaussian Plume Concentration Calculator
Estimate concentration C(x,y,z) from a point source with a steady Gaussian plume model.
- GCD & LCM calculator – greatest common divisor tool
Compute the GCD and LCM for up to 32 integers using Euclid’s algorithm and successive reduction.
- GCD & LCM Calculator — step-by-step
Compute GCD (greatest common divisor) and LCM (least common multiple) with steps Euclidean algorithm, ladder method.
- Gear Ratio Calculator
Calculate bicycle gear ratio, gear inches, development, speed from cadence, and simple gear-pair RPM and torque.
- Genetic drift simulator (Wright–Fisher)
Simulate genetic drift with the Wright–Fisher model.
- Genko yoshi manuscript paper PDF generator
Generate genko yoshi manuscript paper with configurable page size, margins, character grid settings.
- Geothermal Gradient and Heat Flow Calculator
Calculate geothermal gradient and conductive heat flow from two depth-temperature points or a known gradient.
- Gibson Assembly Calculator & DNA Assembly Mix
Plan Gibson or Golden Gate DNA assembly mixes.
- Gradient Generator
Build quick linear or radial CSS gradients from 2 or 3 colors, preview the result, and copy the CSS string in your.
- Graph paper PDF generator
Generate print-ready SVG graph paper in millimeters: Cartesian, polar, log-log, semilog, and isometric grids.
- Growth curve fitter (exponential & logistic)
Fit exponential and logistic growth to time-series data and estimate growth rate r, doubling time, and carrying.
- Habit Tracker Paper (Printable PDF)｜CalcBE
Generate monthly or yearly habit tracker paper as precise millimeter SVG with weekday labels, weekly separators.
- Hardy-Weinberg equilibrium calculator (expected frequency / χ²)
Calculate allele frequencies, expected genotype frequencies, χ², and p-value from observed AA/Aa/aa counts.
- Hash Generator Tool
Generate SHA-1, SHA-256, and SHA-512 hashes for text or files in your browser.
- Hemocytometer calculator (cells/mL & viability)
Calculate cell concentration (cells/mL) and viability (%) from hemocytometer counts and dilution.
- Hex Grid Paper Generator (Printable PDF, flat-top/pointy-top)
Generate printable hex grid paper as PDF or SVG.
- Histogram & cumulative frequency from grouped data
Enter grouped or raw data to build a derived frequency table, histogram (frequency or frequency density).
- House Paint Cost Calculator (materials + labor)
Estimate exterior, roof, trim, fence, and deck paint costs from known areas or house size.
- Hypergeometric probability calculator without replacement
Calculate hypergeometric probabilities without replacement, including P(X=10) for N=60, K=35, n=15.
- IC50/EC50 calculator (4PL/5PL curve fit)
Paste concentration–response data and estimate IC50/EC50 (the 50% point) with 4PL/5PL curve fitting.
- Ideal Gas Law Calculator with Steps
Solve PV=nRT, combined gas laws, and gas density or molar mass with automatic unit conversion.
- Image Resizer & Format Converter
Resize and convert images in your browser. Set width, height, format, and quality, then download—no uploads.
- Images to PDF – combine photos in browser
Convert multiple images to a single PDF with page size, orientation, margins, and fit options.
- Imaging Planner (FOV, Pixel Scale, Resolution)
Plan imaging setup with Field of View (FOV), pixel scale, diffraction limits, and seeing-based sampling guidance.
- Inclusion–Exclusion — at least one & none
Compute.
- Inequality Solver for 1D & 2D
Solve linear, compound, absolute value, quadratic, and rational inequalities with shareable steps, plus half-plane.
- Integer composition calculator - counts, k parts
Calculate integer compositions where order matters. Get counts for 2^(n-1), exactly k parts, bounded parts.
- Integer Partition Calculator (p(n), exactly k parts)
Calculate integer partitions p(n) with options for exactly k parts, max part m, distinct parts, odd/even parts.
- Integration Calculator (numeric methods + steps)
Compute definite integrals with trapezoid, Simpson, adaptive, Gaussian, and Monte Carlo methods.
- Interior Paint Calculator
Estimate interior wall and ceiling paint from room dimensions or known area.
- Interval Timer (HIIT & Tabata)
Analog + digital interval timer for HIIT/Tabata.
- Inverse proportion y=k/x explorer
Explore y = k/x with synchronized formula, table, and graph.
- IPv4 subnet & CIDR calculator – network address, host
Convert any IPv4 address and prefix length into its network address, broadcast address, usable host range.
- JSON Diff Tool
Compare two JSON documents online by structure.
- JSON Formatter & Validator
Pretty-print, minify, and validate JSON in your browser.
- Julian date (JD/MJD) calculator
Convert local date/time and timezone to Coordinated Universal Time (UTC)-based JD and MJD instantly.
- Kd calculator
Fit binding data with one-site or Hill models to estimate Kd.
- Kepler's Third Law Calculator
Use Kepler's third law (T² = a³/μ) to solve orbital period or semi-major axis.
- Kinematics: SUVAT / Projectile / Free Fall (steps)
Solve SUVAT unknowns, 2D projectile motion and free-fall on one page.
- Kruskal-Wallis Test Calculator
Run a Kruskal-Wallis test for 3+ independent groups. Review H, the p-value, tie correction, and rank summaries.
- LaTeX Equation Editor — Live MathJax, palette, templates
An advanced LaTeX equation editor with live MathJax preview, caret-aware palette, templates, history, and one-tap.
- Lens & Mirror Ray Diagram Calculator
Compute image distance, magnification, and rays for thin lenses or mirrors with steps and a live diagram.
- Lens and mirror equation & magnification calculator
Solve thin-lens and spherical-mirror equations to get image distance, magnification, and image type with steps.
- Ligation molar ratio calculator
Calculate required insert mass (ng) and volume (µL) from vector mass, length, and desired molar ratio (e.g., 1:3).
- Likelihood Ratio Calculator
Calculate positive and negative likelihood ratios from TP, FP, TN, and FN.
- Likert Scale Calculator
Paste per-option survey counts and get n, mean, median, mode, standard deviation, Top-2-Box, Bottom-2-Box, NPS split.
- Limiting reagent & yield
Balance reactions and compute limiting reagent, theoretical yield, percent yield, and sample purity with steps logs.
- Limits Explorer — one-sided limits and numeric L'Hôpital
Check indeterminate forms, sample one-sided limits, apply numeric L'Hôpital steps, and view the graph near.
- Linear Equation Solver (Step by Step)
Linear equation solver that logs each same-operation step.
- Linear function y=ax+b explorer
Explore y = ax + b with synchronized formula, table, and graph.
- Linear Regression & Correlation — Scatter, OLS/WLS, R²
Paste x,y[,w] data or upload a CSV to fit OLS, WLS or Theil–Sen regression.
- Linear systems solver – 2×2 and 3×3 equation systems
Solve 2×2 and 3×3 systems of linear equations with Gaussian elimination (RREF), classify solutions, show parametric.
- Linear Systems Solver with RREF Steps (2×2 & 3×3)
Reduce 2×2 and 3×3 linear systems with Gaussian or Gauss-Jordan elimination, log every row operation, keep exact.
- Lined paper PDF generator – ruled paper in mm
Generate lined (ruled) paper as an SVG in millimeters.
- List Shuffler (Random Order Generator) – fair shuffle
Shuffle a list fairly with Fisher–Yates.
- Log Laws Calculator (with steps) – expand & condense
Expand, condense, and evaluate logarithms with shareable steps.
- Long addition & subtraction (decimal carry/borrow)
Follow column addition or subtraction with decimals, carries, and borrowing one place at a time.
- Long Division Calculator with Steps
Enter a dividend and divisor to get long division steps, quotient, remainder, decimal answer, and subtraction work.
- Long Multiplication Calculator with Steps
Learn whole-number long multiplication by following partial products, shifted rows, and the final addition step.
- Lottery Odds Calculator
Calculate jackpot odds, 1 in X probability, expected value, prize tiers, and multi-ticket chances for custom.
- Mann-Whitney U Test Calculator
Compare two independent groups with a Mann-Whitney U test. Review exact or asymptotic p-values without assuming.
- Manual tide event planner with moon phase and sunrise/sunset
Review sunrise, sunset, day length, moon phase, illumination, and manually entered tide events for one location.
- Matrix Calculator — RREF / Solve Ax=b / Inverse
Compute RREF, solve Ax=b, find the inverse, determinant, rank, null space, row and column spaces with detailed.
- MCC Calculator
Calculate Matthews correlation coefficient (MCC), balanced accuracy, precision, recall, specificity, prevalence.
- McNemar Test Calculator
Enter one paired 2x2 table to read exact and asymptotic McNemar test p-values.
- Mean and Standard Deviation Calculator
Paste or type your dataset to compute count, mean, variance, and standard deviation (population N and sample N‑1).
- Mendelian ratio chi-square test calculator
From observed counts and expected ratios (3:1, 9:3:3:1, etc.), calculate χ², df, and p-value.
- Merge PDFs – reorder and combine multiple files locally
Merge PDF files in your browser, reorder them, keep only selected page ranges, and download one combined PDF without.
- Michaelis–Menten fitter (Km, Vmax)
Estimate Km and Vmax by nonlinear fitting of the Michaelis–Menten equation from substrate [S] and initial rate v.
- Modular arithmetic calculator – GCD, inverse & CRT
Compute extended GCD, modular inverses, fast power, CRT and linear congruences with BigInt precision.
- MOI Calculator
Calculate MOI from cell count, infectious titer, and inoculum volume.
- Molar mass / molecular weight
Calculate molar mass from a chemical formula with element counts, mass percent composition, and grams-to-moles.
- Moment Magnitude (Mw) Calculator from Seismic Moment M0
Calculate the seismic moment M0 and moment magnitude Mw from the fault length, width, average slip, and rigidity.
- Momentum & 1D collision calculator
Solve 1D collisions with momentum conservation and restitution to get final velocities and energy change with steps.
- Moon visibility (altitude, rise/set, illumination)
Compute moon altitude curve, moonrise/moonset, transit, moon age, and illumination fraction for a selected date.
- Mosaic Planner Pro Tool
Generate NxM mosaic panel centers from target, Field of View (FOV), overlap, and Position Angle (PA) using gnomonic.
- Multi Timer
Manage multiple countdown timers at once with analog + digital views, fullscreen focus, sound/notifications, presets.
- Multiset permutation calculator
Count distinct permutations when items repeat (anagram count) using n!/(n1!...nk!).
- Multistep yield planner
Plan multistep syntheses, compute overall yield forward/backward, and highlight bottlenecks.
- nCr & nPr Calculator (Permutations & Combinations)
Compute nCr (combinations), nPr (permutations), and factorial (n!).
- NGS coverage calculator (average depth)
Estimate average NGS coverage depth.
- NGS library concentration (ng/µL → nM)
Convert NGS library concentration from ng/µL and fragment length to nM, then calculate normalization dilutions.
- Noise dB Calculator (Addition and Distance Attenuation)
Add sound levels in decibels, estimate free-field distance attenuation, and back-calculate the distance needed.
- Normal Distribution and z-Score Calculator
Calculate normal probabilities, z-scores, percentiles, and inverse cutoffs from the mean and standard deviation.
- NPV & PPV Calculator
Calculate PPV, NPV, sensitivity, specificity, and observed prevalence from TP, FP, TN, and FN, then test how PPV.
- Number Needed to Harm Calculator
Convert absolute risk increase into number needed to harm and review control risk, exposed risk, and signed risk.
- Number Needed to Screen Calculator
Convert screening detection yield into number needed to screen and review prevalence, detection rate, and yield.
- Nutrient load calculator (concentration, flow, time)
Estimate total load (kg) from concentration, flow rate, and period.
- Observability time plotter
Plan when a target is observable with altitude, twilight, air mass, and moon conditions on a single timeline.
- Odds Probability Converter
Convert probability to odds or odds back to probability. Useful for Bayes updates, likelihood ratios.
- Odds Ratio Confidence Interval Calculator
Enter a 2x2 table to read the odds ratio with a 90%, 95%, or 99% confidence interval.
- Odds Ratio from 2x2 Table Calculator
Enter event and non-event counts for two groups to read each group odds and the odds ratio from one 2x2 table.
- Ohm's law and simple DC circuit calculator
Calculate voltage, current, resistance, power, and simple series/parallel equivalents with steps Ohm's law formulas.
- OKLCH Converter – HEX, RGB, HSL to OKLCH & OKLab
Convert one color between HEX, RGB, HSL, OKLCH, and OKLab, then copy perceptual color values for modern design-token.
- Online Alarm Clock
Set alarms in your browser without installing apps. Supports repeats, snooze, sound, notifications, and fullscreen.
- Online Dice Roller (d4-d100, 2d6+3)
Roll d4 to d100 or use notation like 2d6+3.
- Online Stopwatch with Analog + Digital Display
Run a high-precision stopwatch with analog and digital displays, lap tracking, fullscreen, keyboard shortcuts.
- Online Timer (Countdown)
Set an online countdown timer with analog and digital displays, presets, quick adjustments, fullscreen, keyboard.
- Open Channel Flow Calculator (Manning Equation)
Estimate open-channel velocity and discharge with the Manning equation for rectangular, trapezoidal, and circular.
- P-value & Critical Value Calculator
Look up p-values from z, t, chi-square, or F statistics, or find critical values from alpha and degrees of freedom.
- P-wave / S-wave epicenter distance calculator
Estimate epicenter distance from the P-wave and S-wave arrival gap (S-P) and back-calculate the event time.
- Paint Coverage Calculator
Estimate how much paint you need from room size or total area.
- Paper templates hub (lined, grid, Cornell, to-do)
Find lined paper, dot grid, Cornell notes, to-do sheets, habit trackers, graph paper, and more.
- Partial fractions calculator – decomposing rational
Decompose rational functions into partial fractions with polynomial long division, Durand-Kerner factorisation.
- Partial pressure & gas mixing
Apply Dalton's law, two-tank mixing, and wet-gas corrections with step logs and optional van der Waals comparison.
- Pascal's Triangle & Binomial Expansion (with steps)
Generate Pascal rows, combinations, and binomial expansions with BigInt accuracy.
- Passphrase generator (Diceware-style) – random words
Generate a strong passphrase from random words (Diceware-style) locally in your browser.
- Password generator – strong secure random passwords
Generate strong random passwords in your browser with crypto.getRandomValues.
- Pattern String Generator — business IDs & sequences
Generate business-style IDs from a pattern (date, sequence, random).
- Paver Base & Sand Calculator
Estimate paver count, base aggregate volume, and bedding sand from patio or walkway size.
- PCR master mix calculator
Calculate PCR/qPCR master mix volumes from reaction count, stock/final concentrations, overage, well format.
- PCR Primer Tm Calculator
Calculate primer Tm and PCR annealing temperature from DNA sequences.
- PDF compressor – shrink large PDF files in your browser
Reduce PDF size entirely in your browser.
- PDF Form Filler & Flattener – Fill, Flatten & Download
Fill PDF form fields in your browser, preview detected AcroForm controls, choose editable or flattened output.
- PDF highlighter & annotator – markup in browser
Annotate a PDF in your browser with highlights, pen marks, and text notes.
- PDF metadata editor – edit title, author & keywords
View, edit, or clear PDF title, author, subject, keywords, and date metadata in your browser without changing.
- PDF page organizer – reorder, rotate & delete pages
Reorder, rotate, duplicate, or delete PDF pages in your browser.
- PDF sign & stamp tool – add signatures and approval
Create a drawn or image signature, place it on PDF pages, add dates or approval stamps, and export a flattened PDF.
- PDF to EMF converter – preserve vectors & text
Convert PDF to EMF in your browser for Windows Office and drawing workflows.
- PDF to images converter – export PDF pages as PNG
Convert PDF pages to PNG or JPEG in your browser.
- PDF to SVG converter – preserve vectors & text
Convert PDF pages to SVG in your browser while preserving vectors and text positions.
- PDF to text converter – extract text in browser
Extract selectable text from PDFs in your browser.
- Permutation test – exact p-value for A/B and paired
Run a permutation (randomization) test for two independent groups or paired samples.
- Permutations & Combinations with Repetition (n^r, nHr)
Calculate repeated permutations n^r and multichoose values nHr with exact BigInt results or fast.
- Planet Observation Planner
Plan planet observation windows with altitude curves, twilight overlay, moon impact, best-window extraction.
- Poker Odds Calculator for Texas Hold'em
Calculate Texas Hold'em odds in one place: hand probabilities, outs hit rate, and equity versus random opponents.
- Polar Alignment Pro Calculator
Compute pole-star reticle angle, clock position, and time-series drift for practical polar alignment in the field.
- Pomodoro Timer with Analog & Digital Display
Run a pomodoro timer with analog and digital displays, automatic phase transitions, local stats, fullscreen, keyboard.
- Population Attributable Fraction Calculator
Estimate population attributable fraction and population attributable percent from exposure prevalence and group risk.
- Population Attributable Risk Calculator
Estimate population attributable risk from exposure prevalence and attributable risk, or from exposed.
- Population Attributable Risk Percent Calculator
Estimate population attributable risk percent from exposure prevalence with exposed and unexposed risk, or from direct.
- Post-Test Odds Calculator
Start from pre-test probability or prior odds, apply a likelihood ratio, and review post-test odds and posterior.
- Power Analysis Calculator
Plan required sample size, achieved power, or minimum detectable effect for one mean, two means, one proportion.
- ppm/ppb ↔ mg/m³ conversion (gas)
Convert gas ppm or ppb to mg/m³ and back using molecular weight, temperature, and pressure.
- Pre-Test Post-Test Probability Calculator
Convert pre-test probability into post-test probability with LR+ or LR.
- Precision & Recall Calculator
Calculate precision, recall, F1, specificity, prevalence, and accuracy from TP, FP, TN, and FN.
- Pressure Altitude Calculator
Calculate pressure altitude, altitude from pressure, or sea-level pressure from a local reading with standard.
- Primary handwriting paper PDF generator (3-line)
Generate primary handwriting paper with headline + dashed midline + baseline.
- Prime factorization calculator – exponents, divisors
Factor any positive integer into primes, see exponents, divisor counts, the largest prime factor, and copy a shareable.
- Prime Factorization with Steps & Factor Tree
Factor any integer into primes, see every trial division step, compute τ(n), σ(n), φ(n), and draw the factor tree.
- Print DPI Calculator
Estimate effective PPI for a print size from image pixels.
- Probability tree & 2×2 table — AND/OR & complement
Probability tree & 2×2 table tool for AND/OR/NOT and complements.
- Projectile motion calculator
Calculate time of flight, range, maximum height, and required launch speed for a target with projectile-motion steps.
- Protein standard curve calculator (BCA / Bradford)
Build a protein assay standard curve for BCA or Bradford data, fit linear or quadratic models, and estimate unknown.
- Punnett square generator (1- and 2-gene)
Generate a Punnett square from parent genotypes (AA/Aa/aa, AaBb, etc.) and summarize genotype proportions (%/ratio).
- Pythagorean theorem calculator
Solve and visualize a²+b²=c² with a right-triangle diagram and area model.
- qPCR standard curve calculator
Build a qPCR standard curve from Quantity and Ct, calculate slope, intercept, R², and PCR efficiency (%).
- Query String Parser
Parse raw query strings or full URLs, inspect repeated keys, decode values, and copy a normalized query locally.
- RA/Dec to Alt/Az calculator + daily altitude curve
Compute single-time Altitude and Azimuth (Alt/Az) and plot a 24-hour altitude curve with CSV export.
- Radioactive decay/dating calculator
Calculate the elapsed time (age) from the half-life and survival rate (N/N0, %).
- Rainfall to Volume and Flow Rate Converter
Convert rainfall (mm) and area into water volume (m³).
- Random CSV generator – test data & schema JSON
Generate random CSV test data in your browser.
- Random Date Generator, Time Generator & Datetime Generator
Generate random dates, random times, or random datetimes with ranges, weekday filters, exclusions, time windows.
- Random distributions: samplers, tests & visualizers
Generate random samples from distributions, visualize histograms, and sanity-check randomness in your browser.
- Random JSON Generator (Test Data) — array & NDJSON
Generate JSON test data from a schema. Export as JSON array or NDJSON.
- Random Log Generator — Nginx, Apache & JSON logs
Generate fake access logs (Nginx/Apache) or JSONL logs with controllable distributions.
- Random number generator (integers, decimals, seed)
Generate random numbers in your browser: integers or decimals, optional seed, unique mode, and one-click copy.
- Random Picker
Pick one or more random items from a list in your browser. Great for lotteries, giveaways, and classroom activities.
- Random SQL INSERT Generator — Postgres, MySQL, SQLite
Generate SQL INSERT statements from a schema for Postgres, MySQL, or SQLite.
- Random test data generators (CSV, IDs, time)
Create CSV test data, random IDs, and timestamps locally in your browser.
- Random tools – generators, pickers, shuffles
Random generators and pickers that run entirely in your browser: numbers, dates, CSV test data, tokens, UUIDs.
- Random Walk & Markov Chain Visualizer
Run random walk (1D/2D/3D) and Markov chain simulations in your browser.
- Randomness beacon verifier – paste a beacon to verify
Paste a public beacon value to verify a deterministic draw or shuffle.
- Randomness Tests (chi-square, runs, ACF, JB)
Run chi-square, runs, autocorrelation, and Jarque-Bera tests on bit or number sequences.
- Ratio Calculator & Proportion Solver with Steps
Use a ratio calculator and proportion solver with steps.
- RC / RL / RLC Calculator — time constant, cutoff
Analyse RC, RL, and RLC networks with steps formulas.
- Reaction kinetics & half-life
Analyze integrated rate laws, half-lives, 0th/1st/2nd order fits and Arrhenius plots for simple reaction kinetics.
- Reagent table & reaction scale
Build reagent tables from a base amount, convert equiv/mol%/ppm to mmol, grams, and mL, then export or share.
- Regex Tester Tool
Test JavaScript regular expressions online with pattern, flags, match preview, capture groups, and replace output.
- Relative Risk and Odds Ratio Calculator
Enter event and non-event counts for two groups to compare relative risk, odds ratio, and absolute risk difference.
- Repeating Decimal to Fraction Calculator with Steps
Convert repeating (recurring) decimals like 0.1666.
- Resistor Color Code Calculator (4/5/6 Band)
Decode 4/5/6-band resistor color codes (or get colors from a value).
- Resize & Crop PDF Pages – A4, Letter, Custom
Crop and resize PDF pages in your browser.
- Riemann Sums Calculator
Visualize left/right, midpoint, trapezoid and Simpson sums for f(x), compare with an adaptive Simpson reference.
- Risk Difference Calculator
Compare two event-rate groups and review signed risk difference, absolute difference, and each group risk together.
- Risk Difference Confidence Interval Calculator
Enter one 2x2 table to read the risk difference with a 90%, 95%, or 99% confidence interval.
- Risk Ratio Confidence Interval Calculator
Enter a 2x2 table to read the risk ratio with a 90%, 95%, or 99% confidence interval.
- Risk Ratio from 2x2 Table Calculator
Enter event and non-event counts for two groups to read each group risk, the risk ratio, and risk difference.
- ROC AUC Calculator
Calculate a binary ROC curve, AUC, and threshold table from pasted score,label rows.
- Roman Numeral Converter
Convert integers to Roman numerals and Roman numerals back to numbers.
- Roof Paint Calculator
Calculate roof paint area and paint quantity from roof size, slope, roof planes, or known area.
- Rounding & error bands
Round any number, highlight the digit you inspect, and see the error band on a number line.
- Sample Size Calculator
Plan sample size for surveys, means, and balanced A/B tests.
- Sampling & Bootstrap — CLT Explorer (with steps)
Simulate samples from common distributions, bootstrap means or proportions, and see CLT histograms with steps.
- Scientific calculator – trig, logs, powers and degree
Run trig, logs, exponents, and factorials with Deg/Rad modes, keyboard input, memory, and a shareable URL that.
- Seating Chart Generator (Random) — Classroom & Tables
Free online seating chart generator for classrooms and events.
- Secret Santa generator (exclusions) – draw names fairly
Generate Secret Santa assignments in your browser.
- Sector arc length, area & angle calculator
Solve a sector’s arc length l, area A, central angle θ, or radius r with units and a live diagram.
- Semantic Color Tokens
Turn an approved base color into semantic token names for product UI, docs, or marketing.
- Sensitivity and Specificity Calculator
Calculate sensitivity, specificity, false positive rate, false negative rate, balanced accuracy, and prevalence.
- Sequences & Series (Arithmetic / Geometric) — terms
Compute arithmetic and geometric sequences with steps logs: nth terms, partial sums, solving for n or k, two-point.
- Seyes (French ruled) paper PDF generator
Generate Seyes/French ruled paper in millimeters.
- Shuffle bias comparison – naive vs Fisher–Yates
Compare shuffle bias: naive swap-everywhere vs Fisher–Yates (and optional sort(() => random - 0.5)).
- Sidereal Time Calculator
Calculate Greenwich mean sidereal time (GMST), local sidereal time (LST), and optional hour angle from date-time.
- Sign Test Calculator
Run an exact sign test on paired before/after values.
- Signed number line calculator & sign rules
Add, subtract, multiply, and divide signed numbers with a number-line animation for plus/minus moves.
- Significant Figures & Scientific Notation (with steps)
Count significant digits, normalize to scientific notation, and compare textbook vs final rounding for + − × ÷.
- Similarity ratio calculator – side, area, volume
Enter a similarity ratio (small:large) to see side/perimeter, area (square), and volume (cube) ratios with scale.
- Simple harmonic motion (SHM) calculator
Compute SHM period, angular frequency, speed, acceleration, and energy for mass-spring and small-angle pendulum.
- Simple Harmonic Motion Simulator
Simulate SHM with analytic, Euler-Cromer, or RK4 methods and review period, energy, and plots.
- Simple indicator of liquefaction
Visualize shaking, groundwater, and soil factors with a simple educational liquefaction score.
- Simultaneous Equations Solver (steps + graph)
Solve two linear equations with elimination, substitution, and graph views.
- Slope Grade Calculator
Calculate slope grade, angle, rise, run, and slope distance from rise over run or from two elevations.
- Snell's law Refraction Calculator
Calculate refraction angle, critical angle, and total internal reflection with Snell's law steps.
- Solubility product (Ksp) & precipitation
Compare Ksp, Q, and molar solubility to test precipitation and simple fractional ranges.
- Solution preparation recipes
Generate lab-ready recipes from solid reagents or stock solutions and design serial dilution series with steps.
- Split PDF files – extract page ranges or every N pages
Split a PDF into multiple files directly in your browser.
- Square root simplifier with factor tree & steps
Simplify square roots to a√b with factor tree, pairing highlights, and steps.
- Staff paper PDF generator
Generate staff paper in millimeters. Adjust staff spacing, system count (auto/manual), bar guides, lyric lines.
- Standard calculator (history tape & memory)
Perform four‑function math with parentheses and percent, a running tape, and memory slots—fully keyboard accessible.
- Standing Waves Frequency Calculator
List standing-wave mode frequencies and wavelengths for strings and air columns from basic inputs.
- Stars and Bars Calculator
Use the stars and bars method to count combinations with repetition.
- State Color Tokens
Turn approved component token aliases into hover, active, disabled, focus, or selected state tokens.
- Step-by-step solution PDF exporter — multi-language
Build printable, step-by-step solution sheets with numbering styles, language options, and attachments.
- Stirling Numbers Calculator (1st & 2nd Kind)
Generate Stirling numbers of the first and second kind, plus Bell numbers, with fast table output, recurrence details.
- Stoichiometry & limiting reactant
Compute the limiting reactant, theoretical yield, remaining amounts, and percent yield from a balanced chemical.
- Streak Probability Simulator
Estimate the chance of consecutive wins or losses, expected streak starts, and likely longest streaks in one.
- Study timetable (time blocking) PDF generator
Create daily or weekly time-blocking timetables in millimeters with adjustable columns, labels, and margins.
- Sun Position Calculator: Solar Noon, Altitude & Azimuth
Calculate solar noon, solar altitude, azimuth, sunrise, sunset, and day length from latitude/longitude, date.
- Surface & volume nets
Compute surface area and volume for prisms, pyramids, cylinders, cones, and spheres with net diagrams, face.
- Synthetic Time Series Generator — trend, seasonality
Generate synthetic time series data with trend, seasonality, noise, missing values, and outliers.
- T-Test Calculator
Run one-sample, two-sample, and paired t-tests from summary statistics or pasted raw data.
- TAB sheet PDF generator
Generate guitar/bass TAB sheets in millimeters.
- Target yield back-calculator
Back-calculate base and reagent amounts from a target product mass with auto-balanced reactions.
- Taylor & Maclaurin Series — with steps and graphs
Build Taylor and Maclaurin polynomials P_n(x) with symbolic derivatives or fallback fits, then compare f and P_n.
- Team generator – random teams & groups
Split a list of names into random teams or groups in your browser.
- Text Case Converter — upper/lower/title
Convert text between upper, lower, title, sentence, snake_case, camelCase, and kebab-case instantly in your browser.
- Text Diff Tool
Compare two plain text blocks online line by line.
- Theme Color Tokens
Turn one approved base color into light, dark, brand-alt, and high-contrast token bundles.
- Thermodynamic process & PV diagram calculator
Compute work, ΔU, and heat for ideal-gas isothermal, isobaric, isochoric, adiabatic, and polytropic processes.
- Tile, Grout & Adhesive Calculator
Estimate tile count, grout quantity, and adhesive bags from room area or known tiled area.
- Todo checklist paper PDF generator (printable)
Generate printable todo/checklist paper with checkboxes.
- Token Alias Planner
Plan token alias depth and fallback chains across semantic, component, state, and theme layers before naming.
- Token Category Mapper
Decide whether a token belongs in semantic, component, state, or theme layers before naming, audit, or export.
- Token Conflict Checker
Check where one token role creates direct conflicts, shadowed overrides, and redundant layers across theme, state.
- Token Counter
Count characters, words, lines, bytes, and rough token estimates for mixed English and CJK text.
- Token Dependency Graph
Map upstream aliases and downstream token dependents so you can see what breaks before renaming, replacing.
- Token Deprecation Plan
Turn token change scope into a deprecation plan with alias grace, warning channel, freeze timing, and hard-removal.
- Token Fallback Map
Map fallback order, override winner, and last-resort source when semantic, component, state, and theme tokens can all.
- Token generator – secure random strings (base64url, hex)
Generate secure random tokens and random strings locally in your browser.
- Token Impact Simulator
Simulate which branches, tokens, and component surfaces change first when you rename, replace, or remove one token.
- Token Migration Status
Track token adoption, replacement coverage, blockers, and remaining consumers before freeze, deprecation, and removal.
- Token Override Matrix
Compare how one token role changes winners across theme, state, and platform scenarios after fallback order already.
- Token Resolution Debugger
Trace one token from public request through alias hops, layer candidates, and last-resort fallback so you can explain.
- Token Rollout Checklist
Turn token impact estimates into a release checklist for visual diff, coverage, docs, and blocker review before merge.
- Torque, RPM & Power Calculator
Calculate torque, RPM, horsepower, or kilowatts from the other two values.
- Triangle Solver (SSS / SAS / ASA, Area & Circumradius)
Select SSS, SAS, or ASA inputs and compute the remaining sides, angles, area, and triangle diagram.
- Triangle Solver (SSS, SAS, ASA, SSA) with steps
Solve a triangle from sides and angles with SSS, SAS, ASA/AAS, or SSA.
- Triangular Distribution Generator (min/mode/max)
Generate samples from a triangular distribution using min/mode/max and visualize the PDF and histogram.
- TRPG dice check (d20/d100, pools) with PNG sharing
Run d20/d100 checks with advantage/disadvantage, compare vs DC, and roll dice pools to count successes.
- Truncated Normal Generator & Visualizer
Generate samples from a truncated normal distribution with lower/upper bounds and visualize the PDF/CDF and histogram.
- Truth Table & Logic Evaluator — DNF/CNF Simplifier
Build Boolean truth tables up to 10 variables, export canonical DNF/CNF, simplify with Karnaugh or Quine–McCluskey.
- Tsunami Speed & Arrival Time Calculator
Calculate approximate tsunami wave speed and arrival time from average water depth and distance using.
- Twilight, sunrise & sunset calculator
Compute sunrise/sunset, civil/nautical/astronomical twilight, and dark-night duration for your location.
- Unit Circle & Trig Explorer — amplitude, period & phase
Explore y = A·f(bx+φ)+D for sine, cosine, and tangent.
- Unix Timestamp Converter & Epoch to Date Converter
Convert Unix epoch seconds or milliseconds to human-readable date/time and back.
- URL Encoder / Decoder Tool
Percent-encode text, decode strings, and parse full URLs with an editable query parameter list in your browser.
- USLE/RUSLE Soil erosion (simple calc)
Estimate soil erosion loss with the USLE/RUSLE model A=R×K×LS×C×P.
- UUID Generator (v4/v7) – bulk, format, validate
Generate UUID v4 or UUID v7 in bulk, format them (canonical/URN/braces), copy or download, and validate UUIDs with v7.
- Vector Calculator — dot/cross, projection, angle, area
Compute norms, dot, cross (2D/3D), projection, angle, areas, and triple product with steps logs.
- Verifiable random draw (commit-reveal) – auditable
Run a verifiable random draw with commit-reveal logs so participants can verify every draw.
- Voltage divider & LC resonance calculator – gain
Design DC voltage dividers with loading and reverse solves, and compute LC resonance, reactance, Q, bandwidth.
- Wallpaper Roll & Paste Calculator
Estimate wallpaper rolls and paste packs from wall size or known net area.
- Weibull Distribution Generator & Visualizer
Generate random samples from a Weibull distribution and visualize the PDF and histogram.
- Weighted Random Picker & Randomizer
Use this weighted random picker and randomizer to draw winners by weight, ratio, or raffle entries.
- Wilcoxon Signed-Rank Test Calculator
Enter paired before and after values to run a Wilcoxon signed-rank test.
- Word Problem Wizard — percent, ratio, speed
Solve common word problems by selecting a template, entering values with units, and getting equations and simple.
- Work, energy & power calculator
Compute work, kinetic and potential energy change, and average power from force, distance, mass, speed, and height.
- Youden’s J Calculator
Calculate Youden’s J from TP, FP, TN, and FN.
- ΔCt / ΔΔCt calculator (relative expression)
Paste qPCR Ct values to calculate ΔCt/ΔΔCt, log2FC, and fold change.
Education & study
Plan GPA scenarios, track coursework, and set targets for final exams.
- GPA Calculator (Weighted & Unweighted Course Average)
Compute weighted and unweighted GPA with editable scales, Honors/AP bumps, and shareable course tables.
- GPA Calculator — cumulative & final grade needed
Calculate term and cumulative GPA (weighted or unweighted), convert letter↔percent, estimate the minimum final exam.
- CGPA to Percentage Converter
Convert between CGPA and percentage using example mappings (9.5×CGPA or 10×CGPA).
- Deviation Score (T-score) & Percentile Calculator
Calculate z-score, deviation score (T-score / hensachi), and percentile.
- Embed Builder — share links & iframe code
Create CalcBE share links and responsive iframe embeds.
- Grade Calculator
Calculate a weighted course grade or the final exam score needed to reach a target.
- Multiplication Table Generator
Generate printable multiplication tables for 1-12, 1-20, custom sizes, blank practice sheets, skip counting.
- Number Bonds & Fact Family Builder
Build number bonds to 10, 20, 100, or any target, then print missing-part worksheets, answer keys, and fact families.
- Number line & interval visualizer (inequality shading)
Shade inequalities and interval unions on an interactive SVG number line.
- Quick charts from pasted data — scatter / box plot
Paste spreadsheet data to generate scatter and box plots instantly.
Life & health
Track personal indicators while keeping privacy and control offline.
- BMI calculator (kg/cm) – BMI & WHO category
Enter weight (kg) and height (cm) to get your BMI and WHO category instantly.
- BMR & TDEE Calculator
Calculate BMR, TDEE and daily calorie needs using age, sex, height, weight and activity level.
- Ideal Weight Calculator – Devine, Hamwi & BMI Ranges
Estimate ideal body weight with the Devine, Hamwi, Robinson and Miller formulas, set a custom BMI goal.
- Body Fat Percentage Calculator
Estimate body fat percentage with the US Navy circumference method or BMI (Deurenberg).
- Due Date Calculator (LMP, IVF, Ultrasound)
Estimate your pregnancy due date and current gestational age from LMP, conception, IVF transfer, or ultrasound date.
- 1RM (One-Rep Max) & Training Weight Calculator
Estimate your 1RM from weight and reps using common formulas, then convert to training weights by %1RM or target reps.
- Aid Station Fueling Plan
Turn hourly fluid, sodium, drink-carb, and gel targets into aid-station actions with carry limits, refill timing.
- Calorie & Weight-loss Planner
Estimate your TDEE, set a calorie target to reach your goal weight by a chosen date, or see how long it may take.
- Calorie Deficit Calculator
Compare maintenance calories and target intake, then estimate daily calorie deficit, weekly deficit, and rough weekly.
- Calorie Surplus Calculator
Compare maintenance calories and target intake, then estimate daily calorie surplus, weekly surplus, and rough weekly.
- Calories Burned Calculator
Estimate calories burned from body weight, activity MET, and minutes.
- Carb Drink Mix Planner
Turn a per-bottle carb target into practical scoop or serving counts, then check rounded bottle carbs, total carbs.
- Comeback Week Schedule
Turn recovery and return-to-training signals into a seven-day comeback week for session length, rest days.
- Crew Handoff Fueling Plan
Turn crew-access timing into checkpoint-by-checkpoint handoff contents for bottles, mix, gels, and electrolyte backup.
- Dehydration Percent Calculator
Compare a known session-loss estimate against starting body weight and see the percentage body-mass change before you.
- Drop Bag Fueling Plan
Turn a believable race fueling flow into drop-bag placement by checkpoint, including reserve bottles, mix, gels, tabs.
- Electrolyte Bottle Plan
Turn session fluid and sodium targets into a bottle-by-bottle electrolyte plan.
- Electrolyte Drink Mix
Turn one bottle sodium target into tablets, scoops, or serving fractions.
- Electrolyte Needs Calculator
Check whether a workout context still looks like plain-water territory or if electrolyte support deserves more.
- Gel Carb Schedule
Turn a per-hour carb target into gel timing, serving fractions, and checkpoint-by-checkpoint carb totals.
- Heart Rate Zone Calculator (Karvonen, HRR, Max HR)
Find your training heart rate zones in bpm using %HRmax, Karvonen (HRR), or %LTHR.
- Hydration Bottle Plan
Turn one during-workout drink target into a practical bottle and refill plan.
- Hydration Schedule Calculator
Split one daily water target across wake-up, daytime, training, or hot-weather slots, then copy a simple hydration.
- Macro Calculator
Turn daily calories and macro ratios into grams of protein, carbs, and fat.
- Macro Per Meal Calculator
Split daily protein, carbs, and fat grams across 3 meals, 4 meals, or 3 meals plus a snack, then copy a simple.
- Meal Calorie Split Calculator
Split a daily calorie target across 3 meals, 4 meals, or 3 meals plus a snack, then copy the meal-by-meal kcal plan.
- Multi-Day Recovery Plan
Turn the finish-to-breakfast recovery story into a day 1 to day 3 plan for fluid, carbs, protein, easy movement.
- Next-Day Recovery Plan
Turn the remaining evening fluid loss into a next-day recovery note that covers dinner, pre-bed support, breakfast.
- Pet Age Calculator
Estimate dog or cat age in human years and life stage from species, age, and dog size.
- Post-Race Refuel Plan
Turn finish-line fluid loss and body mass into a first-30-minute, first-hour, and first-meal refuel note for drink.
- Pre-Workout Hydration Plan
Turn body weight, start time, and session context into a simple pre-workout hydration plan, then split mL across drink.
- Protein Intake Calculator
Estimate a daily protein intake range from body weight and goal, with quick g/kg guidance for general intake.
- Protein Per Meal Calculator
Split a daily protein target across 3 meals, 4 meals, or 3 meals plus a snack, then copy the meal-by-meal gram plan.
- Race Fueling Pack List
Turn race duration, bottle capacity, mix, gels, and backup margin into a simple pack list after your aid-station plan.
- Rehydration Plan Calculator
Turn a workout fluid-loss estimate into a simple post-workout rehydration plan, then split liters and mL.
- Return to Training Check
Turn recovery signals into a simple return-to-training check for easy, reduced, or delayed training after a hard.
- Running Pace, Time and Distance Calculator
Solve running pace, time, or distance from the other two.
- Session Fueling Plan
Combine fluid, sodium, carb drink, and gel targets into one session note with checkpoints, bottle counts.
- Sleep Cycle Calculator
Find suggested bedtimes or wake-up times using sleep cycles and a fall-asleep buffer.
- Sodium Loss Estimator
Estimate a rough sodium-loss range from sweat rate, session length, heat, and sweat saltiness.
- Steps to Calories & Distance Calculator
Convert steps into distance (km/mi), walking time, and calories burned using height, weight, pace, grade, and terrain.
- Sweat Rate Calculator
Estimate session fluid loss and sweat rate from pre/post workout weight, session duration, and drinks consumed.
- Training Load Rebuild
Plan weeks 2 to 4 after return-to-training with a weekly volume cap, long-session ceiling, and deload trigger.
- Training Ramp Plan
Turn return-to-training readiness into a short ramp plan for first-session duration, week-volume cap, and long-session.
- Water Intake Calculator
Estimate a daily water intake baseline from body weight, activity level, and climate, then review liters, mL, fl oz.
- Workout Hydration Plan Calculator
Turn a known session-loss estimate into simple drink checkpoints during a workout, then see how much fluid may still.
Cooking & kitchen
Convert recipe measurements, scale batches, and stay organised in the kitchen.
- Recipe Scaler (Paste ingredients, resize servings)
Paste a recipe ingredient list and scale it instantly by servings or multiplier.
- Cups to Grams Converter for Flour, Sugar & Butter
Convert cups to grams for flour, sugar, butter, milk, water and more.
- Cake pan and baking sheet size converter
Convert round, square, and rectangular pan sizes to get the batter scaling factor by area or volume.
- Microwave Wattage Converter
Use this microwave wattage converter for time conversion from 1000W or 1100W to 700W, 800W, 900W, or your wattage.
- Oven Temperature Converter (°C, °F, Gas Mark, Fan)
Convert oven temperatures between Celsius, Fahrenheit, Gas Mark, and fan-assisted (convection).
- Oven to air fryer conversion calculator (temp & time)
Convert oven recipe temperature (°C/°F/Gas Mark) and time to air fryer settings as a quick guideline.
Choose a calculator by the job you need done
Use this directory when you already know you need a calculator, but you have not chosen the category yet. Start with the job, then narrow to one category or one page.
Pick a route by task
- Daily math and classroom work: start with Math & Statistics.
- Money, tax, loans, or pricing: start with Finance calculators or the Tax topic hub.
- Date, time, and schedule questions: start with Date & Time calculators.
- Science and engineering checks: move to Science, Physics, Chemistry, or Electronics hubs.
- Broader decision routing: use Topics when the domain is clearer than the category.
Best workflow
- Pick one category from the job list.
- Open one calculator inside that category.
- Return here only if the next problem belongs to another category.
FAQ
When should I use this directory instead of Topics?
Use the calculator directory when you already know you want a calculator category such as finance, math, or date & time. Use Topics when the domain or workflow is clearer than the category.
How do I find one exact page faster?
Use the category filters first, then switch to site search if you know the exact page name or keyword.
What is the difference between calculators and tools?
Calculators answer numeric or logic questions. Tools are better for PDF work, paper templates, random generators, formatting, and other utility tasks.
Are these pages suitable for high-stakes decisions?
They are suitable for planning and education. For legal, medical, tax, or regulated decisions, confirm assumptions and outcomes with official guidance or qualified review.
Start with these calculator hubs
- Finance calculatorsUse this for loans, payments, rates, taxes, and money workflow questions.
- Math & statistics calculatorsOpen this for algebra, geometry, percentages, distributions, and classroom math.
- Science hubMove here for physics, chemistry, biology, electronics, and earth-science routes.
- Topics hubUse Topics when the domain is obvious but the exact calculator category is not.