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Number base converter — offline

Binary, octal, decimal, and hex — converted exactly with BigInt, on your device.

100% private — files never leave your device
Input base:
Binary11111111
Octal377
Decimal255
Hexadecimalff

How it works

  1. 1

    Pick the base of your input number.

  2. 2

    Type the number (0x/0b prefixes and _ separators are fine).

  3. 3

    Copy any of the four representations.

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Frequently asked questions

Are my numbers processed on a server?

No — conversion happens in your browser using BigInt, so even numbers far beyond 64 bits convert exactly.

Which bases are supported?

Binary, octal, decimal, and hexadecimal. Prefixes (0b, 0o, 0x) and underscore separators are accepted on input.

Is there a size limit?

Practically no — BigInt handles arbitrarily large integers with exact precision.