Calculators & converters

Convert integers exactly between bases 2–36, including negative and very large values, with common base results shown together.

Convert length, mass, area, volume, temperature, speed, data size and time, with editable values on both sides.

Find a percentage of a number, calculate what share a part represents, or measure the percentage change between two values.

Count calendar days between dates, or add and subtract days from a date, with an option to skip weekends.

Calculate an exact decimal sum, mean, median, minimum, maximum and population or sample standard deviation for a list of numbers.

Add, subtract, multiply or divide fractions exactly, then see the reduced fraction, mixed number and decimal approximation.

Total time entries without wrapping at 24 hours, subtract durations and convert the result to seconds, minutes or hours.

Generate random integers in an inclusive range, with unique results, sorting and support for numbers beyond JavaScript’s safe integer range.

Measure elapsed time with laps or set a countdown, pause and resume, and export lap records to CSV.