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Number Base Converter
ConversionFree online number base converter. Convert between binary, decimal, hexadecimal, and octal instantly. Useful for color values and bitwise operations.
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Number
All bases
Binarybase 2
11111111Octalbase 8
377Decimalbase 10
255Hexbase 16
FFQuick answers for Number Base Converter
Which bases does the Number Base Converter support?
Binary (base 2), Octal (base 8), Decimal (base 10), and Hexadecimal (base 16). Pick the source base, type a number, and all four representations update at once.
Does it handle very large numbers?
Yes. The conversion uses BigInt under the hood, so it stays exact for numbers far beyond JavaScript's 2^53 safe-integer limit. Useful for hashes, 64-bit IDs, and bitmasks.
Can I convert negative numbers?
Yes. Prefix the input with `-` and every output is shown with the negative sign. The tool does not produce two's-complement representations - for that, you'd apply the bitwise inverse of the magnitude in the chosen width.
Why is my hex value rejected?
Hex digits are 0–9 and A–F (case insensitive). Anything else - punctuation, the `0x` prefix, or a stray space - causes the input to be rejected. Strip the `0x` and any separators and try again.
Is the conversion done in my browser?
Yes. Conversion is pure-JS arithmetic on BigInt and runs locally - nothing about the numbers you enter is logged or sent anywhere.