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Base Converter🔒 100% local
Convert numbers between any bases (2-36). Supports binary, octal, decimal, hexadecimal, and custom bases.
Base Converter: related tools
Converts a whole number from one base to another, with the two bases picked from dropdowns that cover 2 to 20 and then 36. Digits are read as 0-9 and A-Z, converted to a decimal value in the page and written back out in the target base, all inside the tab you are typing in.
Base Converter: how to use it
- Pick the base you are converting from and the base you are converting to.
- Type the number. Letters are upper-cased for you as you type.
- Press Convert, or use Swap first to put the two bases the other way round.
Base Converter: worked example
255 (base 10 to base 16)becomesFFHex output uses upper-case letters.
1010 (base 2 to base 10)becomes10777 (base 8 to base 16)becomes1FFOctal 777 is 511 in decimal, which is 1FF in hex.
9 (base 8 to base 10)becomesInvalid character '9' for base 8A digit that does not exist in the source base is refused, and the message names the character and the base.
Base Converter: when to use it
- Reading a bitmask or a device register written in binary and wanting it in hex.
- Checking an octal file mode from a listing against the decimal value in a config file.
- Working through a base-N exercise where the intermediate decimal value has to be shown.
Base Converter: what it does not do
- Integers only. A decimal point, a minus sign, a leading 0x or an internal space is an invalid character, so 0x10 in base 16 fails on the X and 1 0 in base 2 fails on the space. Whitespace around the number is trimmed.
- The dropdowns skip bases. They run 2 to 20 and then jump straight to 36, so a base such as 24 cannot be selected even though the conversion routine would cope with it.
- Output is a bare number with no prefix or grouping: converting to hex gives FF, not 0xFF.
- Bits are not shown. There is no binary view of the result, no fixed-width or padded form, and nothing larger than the text box can hold is handled.