Calculators

18 calculators for math, fitness, cooking, life events, school and recipe scaling.

No sign-up. No tracking. No ads.

Meeting Cost Calculator

Find out how much your meetings actually cost. Enter attendees, salaries, and duration.

Aspect Ratio Calculator

Resize images and videos keeping proportions. Presets for YouTube, Reels, Instagram, DSLR.

Unit Converter

Convert between units instantly. Length, weight, temperature, area, volume, speed, data size, time, CSS.

Number Base Converter

Convert between binary, octal, decimal, and hex. Live-linked fields. Bitwise inspector.

BMI & Body Calculator

BMI, BMR, ideal weight, TDEE, and macros. Metric or imperial. US Navy body-fat method.

Roman Numerals Converter

Convert between Roman numerals and regular numbers. Supports extended notation up to 3,999,999.

Percentage Calculator

Three calculators in one: X % of Y, what % is X of Y, and percentage increase/decrease between two numbers.

Random Number Generator

Generate random integers in any range, one-off or in batch. Cryptographically random, unique option.

Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin and Rankine. Live three-way conversion as you type.

Number to Words

Spell out any integer in English, from zero to quadrillions. Useful for cheques, legal text, and invoices.

TDEE & BMR Calculator

Daily calorie needs using Mifflin-St Jeor. Activity multipliers + targets for cutting, maintaining and bulking.

Due Date Calculator

Calculate due date and current pregnancy week from LMP or conception. Trimester breakdown + milestones.

Running Pace Calculator

Pace ↔ time ↔ distance. Split tables for 5K, 10K, half-marathon, marathon at any pace you set.

Cooking Measurement Converter

Cups ↔ grams ↔ ml ↔ oz with per-ingredient density. Plus °C / °F / gas-mark for oven temps.

Sleep Cycle Calculator

Wake at the end of a 90-minute cycle (not mid-cycle). Bedtime suggestions or wake-time options.

GPA Calculator

Unweighted (4.0) + weighted (5.0) GPA from courses, grades, credits, and AP / honors / college flags.

Gas Mileage Calculator

MPG (US + UK), L/100km, km/L, cost-per-mile, full trip cost. Multi-currency.

Recipe Scaler

Paste any recipe, change servings — every ingredient quantity scales. Fraction-aware, decimals or pretty fractions.

Average Calculator

Mean, median, mode, range, sum and count from any list of numbers.

Hours Calculator

Add up work time from start/end rows, subtract breaks. Total in h:mm and decimal hours.

Fraction Calculator

Simplify fractions, fraction to decimal and decimal to fraction, mixed numbers.

Ratio Calculator

Simplify ratios to lowest terms and solve proportions A:B = C:?. Scale mixes and recipes.

Scientific Notation

Convert numbers to/from scientific, E-notation and engineering notation.

About this toolkit

A broad collection of free online calculators for math, fitness, cooking, life events, school, finance and everyday conversions. From the basics (percentage, temperature, BMI) to the specialized (TDEE, running pace, recipe scaling, Roman numerals). Browser-based, no sign-up, no ads.

Who uses these tools

Frequently asked questions

Are these calculators really free?

Yes — every calculator in this category is free, no sign-up, no usage limits. No data is uploaded; every calculation runs in your browser.

Do the calculators support metric and imperial units?

Yes — BMI, cooking, running pace, gas mileage and the unit converter all support both. Temperature converter handles Celsius, Fahrenheit, Kelvin and Rankine.

How accurate are the health calculators?

The BMI / TDEE calculators use Mifflin-St Jeor (the most accurate formula for general populations) and standard activity multipliers. They're informational; consult a doctor for medical decisions.

Can I bookmark / share my calculation?

For most tools, no — the inputs are local to your browser. The few that benefit from sharing (random number generator with a seed, for example) explicitly support it.

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