Calculator.io

Calculator.io puts 176 calculators in your pocket — the same tools millions of people use on calculator.io every month, rebuilt as an app whose calculators work with no connection at all.

No account, no sign-up. Open a calculator and get an answer.

MATH — 61 tools Fractions, percentages, ratios, exponents, roots, logarithms, quadratic equations, matrices, prime factors, GCF and LCM, scientific notation, rounding, long division and a full scientific calculator.

FINANCE — 41 tools Mortgage payments and amortization schedules, loans, auto loans, refinance, APR, compound interest, savings, retirement and 401(k), salary and hourly pay, VAT and sales tax, tips, discounts, currency and unit conversions.

HEALTH & FITNESS — 21 tools BMI, body fat, calories, TDEE and macros, ideal weight, BMR, pregnancy and due dates, ovulation, heart rate zones, pace and water intake.

TIME & DATE — 18 tools Date difference, add or subtract days, age, business days, time duration, hours and minutes, time zones, countdowns, timers, alarms and a metronome.

STATISTICS — 15 tools Mean, median and mode, standard deviation, variance, probability, permutations and combinations, confidence intervals, z-score, correlation and sample size.

MISCELLANEOUS — 20 tools Unit and length conversions, fuel economy, concrete and paint estimates, tile and roofing, grades and GPA, dice, random numbers and more.

WHY IT FEELS DIFFERENT

Built for one hand. Every numeric field opens a keypad made for calculators, not the system keyboard: the keys you actually need, a field-to-field walk, and a Calculate button that is always where your thumb is.

Answers you can read. Results come with the numbers that matter — schedules, breakdowns and charts — not a single figure with no context.

Works offline. Every calculator, every formula and every page ships inside the app, so on a plane, in a basement or abroad with no data, it all still works.

Discovery signals