Skip to content
TextArray
100% local

Number base converter

Convert numbers between any bases from binary to base 36, one per line.

Input
Output
Related tools
Binary to text and backEncoding & conversion
Hex to text and backEncoding & conversion
Character code converterEncoding & conversion
Number base converter
Every base from binary to base 36 writes the same numbers with different digits. Paste one number per line, pick the source and target base, and each line converts as you type — decimal to hexadecimal by default, but any pair from 2 to 36 works, including base 36 itself, whose digits run from 0 to z.
The input is forgiving about how numbers are usually written. A 0x, 0b or 0o prefix on a line overrides the From base, so a mixed dump of hex and binary literals converts in one pass. Underscores and spaces inside a number are read as digit separators, the way 1_000_000 appears in modern source code, and a leading minus carries through to the result. Empty lines pass through untouched, keeping a converted column aligned with the original. A character that isn't a digit in the source base stops the conversion with a message naming the exact line, rather than guessing at what you meant.
Show all common bases replaces the target base with a one-line summary — decimal, binary, octal and hexadecimal side by side — which is the fastest way to read a magic constant. Uppercase digits writes A–F instead of a–f, and the 0x-style prefix adds 0b, 0o or 0x to bases 2, 8 and 16, ready to paste straight into code.
The math is exact integer arithmetic at any size: a number with hundreds of digits converts without the rounding that breaks converters built on floating point past 2^53. Everything runs in your browser and nothing is uploaded.
FAQ
Which bases can it convert between?
Any base from 2 to 36, in either direction. Digits run 0–9 and then a–z, so base 36 uses the full alphabet — the same digit set as parseInt and BigInt in JavaScript.
How large can the numbers be?
There is no practical limit. Conversion uses exact integer arithmetic, so a number with hundreds of digits comes out exact — unlike converters built on floating point, which silently round everything past 2^53, about 9 quadrillion.
Why does 0xff convert as hex even when From base is 10?
A 0x, 0b or 0o prefix is an explicit statement of the base, so it overrides the From base setting for that line. Remove the prefix if the characters were meant as digits.
Can it convert fractions?
No — whole numbers only. A decimal point is reported as an invalid digit, because positional fractions rarely convert exactly between bases and a rounded answer would be misleading.
Are my numbers uploaded anywhere?
No. The conversion runs entirely in your browser and your input never leaves your device.