Number Base Converter

Type a number in any base — binary, octal, decimal or hexadecimal — and see it converted to the other three instantly, even for very large integers.

Runs in your browser — nothing is uploaded

Negative numbers are supported with a leading minus sign (for example -FF). Conversions use arbitrary-precision integers, so there is no size limit from floating-point rounding.

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How to use the Number Base Converter

  1. Type or paste a number into any one of the four fields — binary, octal, decimal or hexadecimal.
  2. The other three fields update live with the same value in their bases.
  3. Use the Copy button next to a field to copy that representation to your clipboard.
  4. Use Clear all to empty every field and start again.

Frequently asked questions

Which digits are allowed in each base?

Binary uses only 0 and 1. Octal uses 0–7. Decimal uses 0–9. Hexadecimal uses 0–9 plus the letters A–F (upper or lower case). If you type a character outside the field’s base, an error names the allowed digits and the other fields keep their last valid values.

How large a number can I convert?

Conversions use JavaScript BigInt arithmetic, which handles integers of arbitrary size exactly. Unlike a normal calculator, values beyond 253 are not rounded.

Are negative numbers supported?

Yes. Start any field with a minus sign, for example -255 in decimal, and the converted values in the other bases will also carry the minus sign.

Why did the other fields not update when I typed?

That happens when the current input is not valid in its base yet — for example the letter G in the hexadecimal field. Fix or clear the invalid character and the conversion resumes.

Is my input uploaded anywhere?

No. Everything is calculated locally in your browser and nothing is sent or stored.