Number Base Converter
Type in any base — binary, octal, decimal, hex, or custom 2–36. Exact BigInt math, nothing uploaded.
Edit any field — the rest update. BigInt-exact.
Any integer base from 2 to 36 (digits 0–9 then A–Z).
|n| uses 8 bits
Accepts 0b / 0o / 0x / # prefixes, spaces, and _ digit separators. Negatives supported.
How to convert number bases
- Paste or type a value in binary, octal, decimal, hex, or custom.
- The other fields update live — edit whichever form you have.
- Copy a row, or toggle uppercase for A–Z digits.
- Optional: set a custom base (2–36) for less common radices.
Why base conversion still matters in 2026–2028
Debuggers print hex addresses. Flags and permissions show up as binary or octal (chmod 755). Protocols and dumps use hex bytes. You still need the same integer in four spellings — fast, exact, and private. This page keeps that job tight: linked fields, prefix paste, BigInt so large values do not silently rot past JavaScript's safe-integer limit, and a single custom base for 2–36. No bitwise playground, no float lab, no color picker bolted on.
Working with colors as #RRGGBB? Try the Color Picker. Encoding bytes for transport? Use Base64 Encode / Decode. Checking a digest? Open the Hash Generator.
FAQ
Is my number uploaded?
No. Conversion runs entirely in your browser with BigInt math. Nothing is sent to a server.
Why BigInt instead of normal JavaScript numbers?
JavaScript Number is only exact up to 2⁵³ − 1. Bitmasks, 64-bit values, and long hex strings need BigInt so digits never silently round.
Which prefixes are accepted?
Binary: 0b. Octal: 0o. Hex: 0x or #. Spaces and underscore separators (like 1_000 or FF_FF) are ignored. Paste into the matching field.
What is the custom base for?
Any integer radix from 2 to 36 — digits 0–9 then A–Z. Useful for base-32/36 IDs or quick checks outside the common four.
Does this convert floats or colors?
Integers only. For #RRGGBB as color, use the color picker / palette tools. For Base64 text or files, use Base64 Encode / Decode.
Are negative numbers supported?
Yes. A leading minus works in every field. The bit-length line reports bits of the absolute value.