Calculator
Unit conversion, percentages, radix and equations. 13 free online tools, all running locally in your browser.
Online Unit ConverterFree online unit converter covering 8 categories and 50+ units: length, weight, temperature, area, volume, speed, data storage and time.
Percentage CalculatorFree percentage calculator: find X% of a number, work out what percent one value is of another, and calculate percent increase or decrease with the formula shown.
Base ConverterFree online base converter between binary, octal, decimal, hex and base 36. Accepts 0x / 0b / 0o prefixes and uses BigInt, so huge integers keep full precision.
Statistics CalculatorFree online statistics calculator: count, sum, mean, median, mode, population and sample standard deviation, range, min and max in one pass.
Random Number GeneratorFree online random number generator: set min, max and count to produce integers, unique draws or decimals with a fixed precision, powered by a cryptographic source for draws and codes.
GCD and LCM CalculatorEnter any number of integers to get the greatest common divisor, the least common multiple and the prime factorisation of each number in one pass.
Fraction CalculatorAdd, subtract, multiply or divide two fractions and get the simplest form plus the mixed number, decimal, percentage and full working.
Rounding CalculatorExact decimal rounding across six modes — half up, banker's, ceiling, floor, toward zero and away from zero — with differences.
Percentile CalculatorFrom one dataset: any percentile, the common ones, a full table, and the rank of a specific value.
Roman Numeral ConverterConvert both ways from 1 to 3999, recognising all four subtractive forms, plus the symbol sum and length.
Area and Volume ConverterConvert between area and volume units — m², mu, hectare, acre, ft², litres, gallons and more.
Scientific Notation ConverterConvert between ordinary numbers and scientific notation, with significant-digit control and exact expansion for huge and tiny values.
Equation SolverSolve linear and quadratic equations, systems of two linear equations and proportions, with discriminants and exact fractions.