Number Base Converter
Convert between binary, octal, decimal and hexadecimal — or any base from 2 to 36 — instantly as you type, with built-in validation.
How it works
A number's value is the same no matter how it's written — only the base (the count of distinct digits) changes. This tool reads your input in its source base, then re-writes that exact value in every other base.
Pick the source base
Tell us how to read your input — binary, octal, decimal, hex, or any base from 2 to 36. Digits use 0–9 then A–Z.
Type your number
Conversions update live as you type. Invalid digits for the chosen base are flagged straight away, so you never get a silent wrong answer.
Copy any result
Grab binary, octal, decimal, hex, or a custom base with one click. Big numbers are handled exactly using BigInt — no precision loss.
Private by design. Every conversion runs entirely in your browser with plain JavaScript. Your numbers are never sent anywhere — we never see them.