Free online calculators

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. Includes price-yield curve, CSV export.

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 | Room Size to BTU/h & kW.
  Estimate room AC capacity from floor area or room dimensions.
• Dimensional Weight Calculator | Shipping Chargeable Weight.
  Calculate parcel volume, dimensional weight, and chargeable shipping weight.
• Screen Size Calculator | Dimensions, Distance & PPI.
  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 | Skip Weekends.
  Count calendar or business days between two dates, exclude custom weekend patterns and holiday lists, and jump forward.
• Time zone converter – instant world clock with multiple.
  Enter a date and time to convert between time zones, with automatic daylight‑saving shifts, presets for major cities.
• Time Duration Calculator (Add & Subtract Time).
  Use this time duration calculator to add or subtract time, work hours, shifts, and breaks in HH:MM or HH:MM:SS.
• Age Calculator (How old am I?) from Date of Birth.
  Find your exact age from date of birth in years, months, and days, plus days until your next birthday. Optional.
• Speed–Distance–Time Calculator with Pace & ETA.
  Calculate speed, distance, or time from the other two.
• Best Meeting Time Across Time Zones | Time Zone Meeting.
  Find the best meeting time across time zones using working-hour overlap, ranked suggestions, and a shareable meeting.
• Event Countdown (Time Remaining).
  Show time remaining until a target date/time with an analog + digital display.

Math & statistics

Solve common classroom and analytics problems without spreadsheets.

• Pi Approximation Explorer | Polygons, series, Monte Carlo.
  Compare polygon, Gregory, Nilakantha, and Monte Carlo approximations of pi with charts, errors, examples.
• Pi Algorithm Race | Compare Gregory, Nilakantha, Machin,.
  Race Gregory, Nilakantha, Machin-like, and Chudnovsky pi algorithms with fixed-time and fixed-digits modes, charts.
• Pi Digits Generator | First n digits with Chudnovsky.
  Generate the first n digits of pi with a Chudnovsky-based browser tool.
• Pi Digit Lab | Search and jump within the first n digits of pi.
  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.

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.
• 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.
• Worksheet & Quiz Auto-Generator (steps & PDF).
  Worksheet & quiz auto-generator with steps (PDF) - linear, quadratic, factoring, fractions, ratios.

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. Copy a shareable result link.
• BMR & TDEE calculator – daily calorie needs and energy.
  Estimate your basal metabolic rate and total daily energy expenditure with the Mifflin-St Jeor equation.
• 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, and compare.
• Body Fat Percentage Calculator | US Navy & BMI.
  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.
• Calorie & Weight-loss Planner | TDEE, Targets.
  Estimate your TDEE, set a calorie target to hit your goal weight by a chosen date, or see how long it will take.
• Heart Rate Zone Calculator.
  Find your training heart rate zones in bpm using %HRmax, Karvonen (HRR), or %LTHR.

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. Handles fractions like 1 1/2 and ½.
• 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.
• 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

1. Pick one category from the job list.
2. Open one calculator inside that category.
3. Return here only if the next problem belongs to another category.

FAQ

Start with these calculator hubs

• Finance calculators
  Use this for loans, payments, rates, taxes, and money workflow questions.
• Math & statistics calculators
  Open this for algebra, geometry, percentages, distributions, and classroom math.
• Science hub
  Move here for physics, chemistry, biology, electronics, and earth-science routes.
• Topics hub
  Use Topics when the domain is obvious but the exact calculator category is not.