Number Base Converter
Enter a number and the base it is written in to see it in other bases.
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Number bases
- Binary (base 2) uses 0 and 1, the language of computer hardware.
- Octal (base 8) uses digits 0–7, for example in Linux file permissions (chmod 755).
- Decimal (base 10) is everyday counting.
- Hexadecimal (base 16) uses 0–9 and A–F. It is used for colours (#FF8800), memory addresses and MAC addresses, because one hex digit is exactly 4 bits.
How conversion works
Each digit is multiplied by a power of the base: FF in hex is 15 × 16 + 15 = 255. To go the other way, divide repeatedly by the new base and read the remainders backwards. This converter uses exact big-number arithmetic, so even 64-bit values like 18446744073709551615 (FFFFFFFFFFFFFFFF) convert without rounding. You can type prefixes such as 0x, 0b and 0o, and spaces and underscores are ignored. Bases above 10 use letters (A = 10 … Z = 35).
Free to useNo software to install — works in any modern browser.
No signup neededOpen the tool and start straight away.
Runs in your browserNothing you enter is sent to a server.
Works on mobileSame tool on your phone, tablet or desktop.
How it works
- Enter — type or paste your values or text.
- Get the result — it is worked out in your browser.
- Adjust — change the inputs to compare, or copy the result.
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