MMaxTools

IBAN Validator

Validate international bank account numbers — structure and mod-97 checksum.

The IBAN Validator checks international bank account numbers for both structure and authenticity: it verifies the two-letter country code is known, the total length matches that country's standard, and the ISO 7064 mod-97 checksum is correct.

IBANs standardize bank accounts across 70+ countries — DE89 3704 0044 0532 0130 00 for Germany, GB29 NWBK 6016 1331 9268 19 for the UK. The mod-97 check catches almost any single-digit error or transposition, which is why payment systems validate it before routing.

The validator covers 40+ country formats with their exact lengths and reformats your input into readable 4-character groups. A passing checksum confirms well-formedness — the account's existence is a separate question. Runs locally in your browser.

Checksum invalid — check digits are wrong.

Validation checks the country-specific length and the ISO 7064 mod-97 checksum — the same checks banks run. A valid checksum confirms the IBAN is well-formed, not that the account exists.

How to use the IBAN Validator

  1. Paste or type the IBAN (spaces are fine).
  2. Read the structure verdict — country and length.
  3. Check the mod-97 checksum result.
  4. See the grouped, formatted IBAN.
  5. Fix and re-validate if flagged.

Frequently asked questions

How does the mod-97 check work?

The first four characters (country and check digits) move to the end, letters become numbers (A=10 … Z=35), and the resulting integer modulo 97 must equal 1. The tool performs this exact ISO 7064 calculation.

Why are IBAN lengths different per country?

Each country defines its own structure inside the two-letter prefix — Germany uses 22 characters, France 27, Malta 31. The validator knows each country's standard length and flags mismatches.

Does validation mean the account exists?

No — it confirms the IBAN is well-formed and checksum-valid. Whether the account is real and open can only be verified by the receiving bank during a payment.