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IBAN validator

Check whether an IBAN is structurally valid: the right length for its country and a passing ISO 13616 mod-97 checksum. Format validity catches typos — it doesn’t confirm the account exists. Need it in code? Hit the IBAN API.

Runs entirely in your browser — nothing is sent to a server. A valid IBAN format does not mean the account exists or is active.

How IBAN validation works

  1. Strip spaces and upper-case the input.
  2. Confirm the length matches the country (first two letters).
  3. Move the first four characters to the end.
  4. Replace each letter with two digits (A=10 … Z=35).
  5. The IBAN is valid if that number mod 97 equals 1.

IBAN format by country