Number Base Converter

Convert whole numbers between binary (base 2), octal (base 8), decimal (base 10), hexadecimal (base 16) and any base from 2 to 36. Very large numbers are converted exactly, without rounding.

Number in any base 2–36 → Binary, Octal, Decimal, Hexadecimal, Custom base

Runs in your browser

Free, no sign-up

How to use Number Base Converter

Type a number.
Choose the base it is written in (e.g. Binary).
See it in binary, octal, decimal, hexadecimal and a custom base at the same time.

Examples

Binary 1010 = decimal 10 = hex A
Decimal 255 = hex FF = binary 1111 1111
Hex 0x1F = decimal 31

Supported formats

Input	Number in any base 2–36
Output	Binary, Octal, Decimal, Hexadecimal, Custom base
Processing	On your device, in the browser (no upload)

Limitations to know

Whole numbers only (no fractions).
Prefixes like 0x, 0b and 0o are accepted and ignored.

Privacy: Number Base Converter runs entirely in your web browser. Your Number in any base 2–36 data is not uploaded, stored or shared, and nothing about its contents is sent to analytics.

Frequently asked questions

How do I convert binary to decimal?

Multiply each digit by a power of 2 from right to left and add them: 1011 = 1×8 + 0×4 + 1×2 + 1×1 = 11.

Why does hexadecimal use letters?

Base 16 needs 16 digits, so A–F represent 10–15. FF in hex is 15×16 + 15 = 255.

Last updated 31 October 2026 · Maintained by the ZippyToolkit team