Number Tools
Base conversion, Roman numerals, number words, primes, percentages and more.
Number Base ConverterConvert integers between bases 2–36.Hex / Decimal / Binary Live ConverterEdit hex, dec, oct and bin simultaneously — all stay in sync.Roman Numeral ConverterConvert between Roman numerals and Arabic numbers.Number to Words ConverterSpell out numbers in English words (cheques, captions).Percentage CalculatorPercent of, increase/decrease and ratio problems.Random Number GeneratorCryptographically random integers in any range.Number FormatterThousands separators and fixed decimals for any locale.Factorial CalculatorExact big-integer factorials.GCD & LCM CalculatorGreatest common divisor and least common multiple of a list.Prime Number CheckerTest primality and show the smallest factor.