Converters

Bases, Roman numerals, numbers spelled out in words, ordinals and scientific notation.

9 generators

Binary numbers

List a range of integers in base 2, with optional 0b prefix, nibble grouping and zero-padding to a fixed bit width.

Convert fractions to decimals and back — exactly, including repeating decimals, with the fraction reduced to lowest terms.

List a range of integers in base 16, with optional 0x prefix, byte-pair grouping and zero-padding to a fixed width.

Convert a number between any two bases from 2 to 36, with exact big-integer arithmetic and no precision loss.

Spell any number out in words in eight languages, on either scale, with cheque wording and the British “and” as options.

Ordinal numbers with the right ending in eight languages — including the 11th, 12th and 13th exception that catches most hand-written rules.

Percent of a number, percent change, reverse percentages, and percentages as decimals and fractions — worked out exactly, line by line.

Turn a number into Roman numerals, read a numeral back into digits, or print a whole range as a conversion chart.

Convert between plain decimals, scientific notation, engineering notation and SI prefixes — with exact digit handling and significant-figure control.