Number Base Converter
Convert numbers between binary, octal, decimal and hexadecimal.
Runs entirely in your browser.
Your data never leaves this device and is never sent to our servers.
Binary
Octal
Decimal
Hexadecimal
Different bases suit different jobs: hexadecimal for colours, memory addresses and byte values; binary for flags and bitmasks; octal for Unix file permissions. This converter shows all four at once, so you never have to convert twice.
How to use it
- Enter the number.
- Choose which base you entered it in.
- Read all four representations.
Not working as you expect? Report a problem with this tool.
Frequently asked questions
Do I need the 0x or 0b prefix?
No. Prefixes are stripped automatically, so both 0xFF and FF work.
Why is hexadecimal used for colours?
Each pair of hex digits maps exactly to one byte, so #RRGGBB gives one byte per channel with no ambiguity.