Convert between any radix from 2 to 36 — plus custom alphabets that go beyond 36 symbols.
Why this exists. A plain base-2/8/10/16 converter only covers the basics. Real-world encoding needs Base58 (Bitcoin addresses, where 0/O/I/l are dropped to avoid confusion), Base62 (URL shorteners, mixing 0-9+a-z+A-Z), and Crockford Base32 (case-insensitive, no I/L/O/U). This tool is the meta-converter that handles the whole base-N space.
How it works. Give it an input value, the source base (or a preset/custom alphabet), and the target base. The decoder maps each character to its numeric value using the alphabet, assembles a BigInt, then re-encodes into the target alphabet. Digits above 9 use a-z by default (standard positional notation).
The presets.
- Base58 (Bitcoin) — "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" (no 0, O, I, l).
- Base62 — "0-9A-Za-z", used by URL shorteners and ID generators.
- Crockford Base32 — "0123456789ABCDEFGHJKMNPQRSTVWXYZ" (decodes I/L as 1, O as 0); designed for human entry.
Custom alphabet. Paste any string of unique characters; its length becomes the base. Useful for proprietary ID schemes, shuffled alphabets, or obfuscation.
Tips.
- Leading zeros are not meaningful in positional notation; the converter drops them.
- For very large inputs (hundreds of digits), conversion uses BigInt so it stays exact.
- Hex ↔ decimal ↔ binary round-trips are lossless; text↔number conversions depend on alphabet consistency.