Number Base Converter

Convert numbers between binary, decimal, hexadecimal, octal, and any base from 2 to 36. Type in any field and the rest update instantly - arbitrary-size numbers supported via exact big-integer math.

Prefixes (0x, 0o, 0b) Digit grouping

Decimal · base 10

Hexadecimal · base 16

Octal · base 8

Binary · base 2

Base 32 · custom

About Number Bases

A numeral system's base (or radix) is the number of unique digits used to represent numbers. Decimal (base 10) uses digits 0-9, hexadecimal (base 16) adds the letters A-F, and bases beyond that continue through the alphabet up to base 36. This converter uses exact big-integer arithmetic, so even numbers far larger than JavaScript's safe integer limit of 2⁵³-1 convert without losing precision.

Decimal	Binary	Octal	Hexadecimal
10	1010	12	a
255	11111111	377	ff
1024	10000000000	2000	400
65535	1111111111111111	177777	ffff