IBAN Validator

Country Format and Checksum

The IBAN validator checks the country’s length and domestic-account character pattern before checking the checksum. IBAN means International Bank Account Number.

The first two letters select a format from the SWIFT IBAN Registry. Two digits follow, then the domestic account part. A country’s pattern sets which positions accept letters or digits.

Ordinary spaces are accepted and lowercase letters are checked as uppercase. Your original entry stays in the input, beside a normalised result. Other characters are refused. An unsupported country produces a separate result and no checksum check.

The checksum follows the MOD 97 method used by ISO 13616. The first four characters move to the end, letters become numbers from A = 10 to Z = 35, and division by 97 must leave 1.

Your entry stays on this page. The tool sends no bank details and saves nothing in browser storage or the page address. Clear entry removes the identifier and its result. Reloading, leaving or returning through browser history also clears it.

What a Passing IBAN Means

A passing IBAN matches the supported country’s length and character pattern, and its checksum passes. The result does not confirm a live account, beneficiary name, payment route or authority to send money.

SWIFT’s published example GB29 NWBK 6016 1331 9268 19 has country code GB for the United Kingdom and 22 characters without spaces. Its four-letter bank part and remaining digits match the country pattern. Its checksum leaves remainder 1, so all checks pass.

Changing only the last character to GB29 NWBK 6016 1331 9268 18 preserves the country format and length. Its checksum leaves remainder 71, so the tool reports “Checksum fails”. These are demonstration entries, not payment instructions.

If a check fails, compare the IBAN with the original bank record. Before preparing a payment, confirm the beneficiary and payment instructions through your usual approval procedure.