How to use
- Type a number into the field for its base: BIN, OCT, DEC, HEX or the custom-base field.
- For the custom field, pick a base from 2 to 36 (digits 0–9 and letters a–z).
- Copy any result with the button next to it. Optionally group binary digits into 4-bit nibbles.
FAQ
Is there a limit on number size?
Practically no: the conversion uses BigInt, so numbers with hundreds or thousands of digits convert exactly, without losing low-order digits the way regular JavaScript numbers do.
How do I enter negative numbers?
Put a minus sign in front, e.g. -255. Results are shown with a minus sign (-ff, -11111111). Two’s complement representation is not used.
Can I paste numbers with 0x, 0b or 0o prefixes?
Yes. A 0x prefix in the HEX field, 0b in BIN and 0o in OCT is ignored. Spaces, underscores and apostrophe separators are skipped too.
Which characters are valid in bases above 10?
Digits 0–9 and Latin letters: a = 10, b = 11 … z = 35. Letter case does not matter. If a character is not valid for the selected base, the field shows an error.