Crockford Base32

Client

Douglas Crockford’s Base32 uses digits and letters with I, L, O, and U left out, no = padding in the encoded form, and common OCR substitutions on decode. It is not the same as RFC 4648 Base32 on this site.

See also RFC 4648 Base32.

Workspace

Paste text, run encode or decode—the field updates in place for quick copy.

Crockford Base32

?

Alphanumeric alphabet (no I, L, O, U) with no = padding in the encoded form. For MIME-style A–Z2–7 and padding, use the RFC 4648 Base32 page.

On decode, O/o are treated as 0 and I/i/L/l as 1, as in Douglas Crockford’s spec.

Common use cases

  • Generate or verify human-friendly identifiers that avoid ambiguous I, L, O, and U in the alphabet.
  • Compare with RFC 4648 Base32 when you need = padding or a standard MIME alphabet instead.
  • Decode a pasted value where someone typed O for zero or I for one.

Common mistakes to avoid

  • Expecting standard Base32 (RFC 4648)

    That alphabet uses A–Z2–7 with padding. Crockford’s set is 0–9 and A–Z with four letters removed—use the other tool when you need RFC compliance.

  • Using letter U in the string

    U is not part of the Crockford alphabet. If you need U, check that the data was really encoded in this format.

  • Assuming encryption

    This is an encoding, not a cipher. Anyone can decode a string that uses the public alphabet.

FAQ

Why no padding character?

Crockford’s design omits = padding; length is derived from the bit stream. The decoder ignores accidental trailing = the same way the RFC 4648 page strips padding when needed.

Is this the same as the Base32 page?

No. The RFC 4648 page uses a different 32 symbols and = padding. Pick the one that matches your reference implementation.

Does data leave the browser?

No. Encode and decode run only on your device.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • crockford base32 online
  • crockford base32 encode decode
  • base32 no padding human alphabet
  • human readable base32 no equals

More tools

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