Developer Tools
Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal.
Free foreverRuns in your browserNo sign-up
About the Number Base Converter
Different number systems suit different jobs: binary for bits, hexadecimal for colours and memory, octal for permissions, and decimal for everyday maths.
Enter a number and its base, and this tool shows the same value in binary, octal, decimal and hexadecimal at once.
It uses arbitrary-precision integers, so even very large numbers convert accurately, all in your browser.
Key features
- Binary, octal, decimal and hex together
- Handles very large integers precisely
- Copy any result in one click
- Runs entirely in your browser
How to use
- 1Type a number and pick the base it is written in.
- 2See the value in every other base instantly.
- 3Copy the result you need.
Frequently asked questions
- How big a number can it handle?
- It uses arbitrary-precision integers, so it converts numbers far larger than a normal 64-bit value without losing accuracy.
- Does it support prefixes like 0x or 0b?
- Yes. Common prefixes such as 0x, 0b and 0o are ignored so you can paste values directly.