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.
Favourites
Your saved calculators appear here and in the home page section.
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.
- Password generator – strong secure random passwords | CalcBE
Generate strong random passwords in your browser with crypto.getRandomValues.
- Acid–base pH
Solve acid–base pH for strong and weak acids and bases, plus strong acid–strong base mixtures.
- Algebra simplifier with colors for like terms | CalcBE
Expand with distribution, color-match like terms, and simplify step by step.
- Binomial Test Calculator | Exact p-value for one proportion | CalcBE
Enter successes, trials, and a null proportion to read exact binomial-test p-values.
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.
- 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.
Simple DCF calculator with FCF paste input, Gordon growth or exit multiple terminal value, sensitivity table, CSV.
- 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 EMI (Equated Monthly Installment) 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).
- Interest Rate Converter (APR, APY, EAR).
Use this interest rate converter to switch between APR, APY/EAR, monthly, and daily rates, or run the reverse.
- 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 Chart.
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 your monthly deposits will grow, or estimate.
- 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.
- 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.
- Screen Size Calculator.
Convert screen diagonal into real width and height, estimate viewing distance, and calculate PPI or pixel pitch.
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.
- Time Calculator.
Add or subtract hours, minutes, and seconds for shifts, breaks, overtime, invoices, 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.
- 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.
Enter your age and a reference date to estimate what year you were born and the possible birth-date range.
- Event Countdown (Time Remaining).
Show time remaining until a target date/time with an analog + digital display.
- 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.
- Week Number & Fiscal Year Calculator.
Find ISO week numbers, calendar quarters, and fiscal years for any date.
- 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.
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 (T-chart) 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.
- 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.
- 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 Among 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 (collision probability) calculator.
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.
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 Calculator.
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 PDFs by text – browser-only diff tool.
Upload two PDFs, extract their text locally, and highlight differences by line or paragraph.
- 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.
- Crop & resize PDF pages – adjust size, margins.
Crop and resize PDF pages in your browser.
- 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.
- Data Transfer Time Calculator (Size, Speed, Time).
Calculate transfer time, required speed, or transferable data size with bit/byte and SI/IEC unit conversion.
- 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.
- 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 roller (d4 to d100, 2d6+3, PNG).
Roll d4 to d100 or use notation like 2d6+3.
- 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 Modulus Calculator With Steps.
Enter apparent magnitude, absolute magnitude, or distance to solve the distance modulus formula with steps.
- Distance/azimuth calculator for two latitude.
Calculate the distance and direction (initial/terminal) from the latitude and longitude of two points.
- 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 the saturation concentration and % saturation of dissolved oxygen (DO) from water temperature, salinity.
- 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 chimney height (simple plume rise) calc tool.
Approximate plume rise Δh and effective chimney height He using the Briggs formula (simplified).
- 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 CO₂ emissions from electricity from the amount of electricity (kWh/Wh/MWh) and the emission factor.
- 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 & KL Divergence Calculator.
Calculate entropy, cross-entropy, KL divergence, and JS divergence from probability vectors P and Q.
- Epoch Converter.
Convert Unix epoch seconds or milliseconds to UTC and local time, or parse ISO 8601 dates back to timestamps.
- Epoxy mix ratio calculator (weight & 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.
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.
- 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 Calculator.
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 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 on 3 or more paired groups.
- Fullscreen Clock.
Show a large fullscreen clock in your browser with analog and digital views, seconds toggle, timezone options.
- 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.
- 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/heat flow (geothermal) calc.
Calculate the geothermal gradient dT/dz from two depth points (z1, z2) and two temperature points (T1, T2).
- 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 PDF generator (chemistry, crystals, maps).
Generate hex grid paper in millimeters with flat-top or pointy-top orientation, custom spacing, margins, and clean 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 exact probability, cumulative tails, and ranges for hypergeometric draws without replacement.
- 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 third law (T^2 = a^3/mu) 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 on 3 or more independent groups.
- LaTeX Equation Editor — Live MathJax, palette, templates.
A premium 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.
- 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 LHopital.
Check indeterminate forms, sample one-sided limits, apply numeric LHopital 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 Transformer (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.
Divide numbers with steps long division. Get the quotient, remainder, optional decimals, and each subtraction row.
- Long Multiplication 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.
Enter two independent groups to run a Mann-Whitney U test.
- 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 PDFs in your browser, reorder files, choose page ranges, and download with no upload.
- 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.
- Moment magnitude Mw calc (fault→M0→Mw).
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 Calculator.
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 calc (dB addition/distance attenuation).
You can add dB of multiple sound sources, attenuate by distance (estimate free sound field), and back-calculate.
- Normal Distribution 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.
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 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 (Manning method) flow velocity/flow calc.
Estimate open-channel flow velocity and discharge with Manning method for rectangular, trapezoidal, and circular.
- 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.
- Page numbers & watermarks – stamp PDFs in browser.
Add page numbers or text watermarks to a PDF entirely in your browser.
- 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 melting temperature (Tm) and PCR annealing temperature (Ta) from DNA sequences.
- PDF compressor – shrink large PDF files in your browser.
Reduce PDF size entirely in your browser.
- PDF form filler & flattener – complete forms and lock.
Fill PDF form fields, preview highlights, keep fields editable or flatten them, and download instantly.
- PDF highlighter & annotator – markup in browser.
Highlight, draw, and place text notes on PDFs in your browser.
- PDF metadata editor – edit title, author & keywords.
Read and update PDF metadata such as title, author, subject, keywords, and dates entirely in your browser.
- 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 signature, place it on pages, add dates or approval stamps, and export a signed PDF.
- PDF to EMF converter – preserve vectors & text.
Convert PDF to EMF in your browser while preserving vectors and text positions.
- PDF to images converter – export PDF pages as PNG.
Convert PDF pages to PNG or JPEG entirely 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 text from PDFs entirely in your browser.
- PDF Tools (browser-only).
A fast, private PDF toolkit that runs entirely in your browser: compress, merge, split, convert images, extract text.
- Permutation test – exact p-value for A/B and paired.
Run a permutation (randomization) test for two independent groups or paired samples.
- Planet Observation Planner.
Plan planet observation windows with altitude curves, twilight overlay, moon impact, best-window extraction.
- Poker odds calculator.
Calculate Texas Hold'em odds in one place: hand probability, outs hit rate, and equity versus random opponents, using.
- 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.
- 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 & Proportion Solver — Steps + Percent.
Simplify ratios, solve proportions, and convert percentages with steps working.
- RC / RL / RLC Calculator — time constant, cutoff.
Analyse RC, RL, and RLC networks with steps formulas.
- Reaction kinetics & half-life.
Analyse 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.
- Repetition calculator – n^r & nHr (multichoose).
Calculate repeated permutations n^r and multichoose values nHr with exact BigInt results or fast.
- Resistor Color Code Calculator (4/5/6 Band).
Decode 4/5/6-band resistor color codes (or get colors from a value).
- Riemann Sums Calculator.
Visualise 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 the absolute risk.
- 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 & 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.
Typical factors that affect liquefaction during earthquakes (intensity of shaking, shallowness of groundwater level.
- 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.
- Solar altitude/azimuth/sunrise/sunset/day length.
Calculate solar altitude, azimuth, sunrise, sunset, day length, and solar noon from latitude/longitude, date.
- 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 table (first & second 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.
- Surface & volume nets.
Compute surface area and volume for prisms, pyramids, cylinders, cones, and spheres with synced 3D sketches and nets.
- 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.
- Tide, moon phase, sunrise & sunset calculator.
Review sunrise, sunset, day length, moon phase, illumination, and manually entered tide events for one location.
- 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.
- 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, syncing the unit circle and graph as you change amplitude.
- 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).
Simple calculation of soil runoff using the multiplication model A=R×K×LS×C×P of USLE/RUSLE.
- 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 and 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.
- Zenkaku/Hankaku Converter – kana, fullwidth/halfwidth.
Convert Japanese text between fullwidth/halfwidth and Hiragana/Katakana in your browser.
- 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 ↔ Percentage Converter (Educational).
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.
- 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 and 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.
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.
- 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.
Convert cups, tbsp, tsp, ml ↔ grams/oz using ingredient densities, then scale the whole recipe with one slider.
- Cake pan size converter - round, square & sheet pans.
Convert round, square, and rectangular pan sizes to get the batter scaling factor by area or volume.
- Microwave Wattage Time Converter.
Convert microwave cooking time between wattages such as 1000W, 900W, 800W, and 700W.
- 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.