Dev Utilities
Check an IBAN's structure and mod-97 checksum
The IBAN validator checks a bank account number against the international IBAN format and reports whether it is structurally sound. Payment developers use it to catch malformed numbers before they reach a bank API or a SEPA test. The check strips spaces, uppercases letters, verifies the two-letter country code against 73 entries with their exact per-country lengths, then applies the ISO 7064 mod-97 checksum. A passing result names the country; a failing one says why.
How to use IBAN Validator
- Open IBAN Validator in the Toolbox101 app.
- Paste the IBAN into the
Inputbox. Spaces are fine, and lowercase letters are accepted. - Read the verdict in the
Outputbox:Valid IBAN (Country: Germany)on success, or anInvalid IBAN:line naming the failed check, such aschecksum mismatch. - Click
Copyif you need the verdict text, or correct the digits and watch the check rerun.
Worked example
IBAN Validator returns the output below for this input.
Input
DE89 3704 0044 0532 0130 00Output
Valid IBAN (Country: Germany)Check it yourself: open IBAN Validator and enter the same input.
Frequently asked questions
What exactly does the validator check?
It checks three things: the country code appears in its table of 73 countries with the exact IBAN length each one uses, every remaining character is a valid IBAN character, and the rearranged digits leave a remainder of 1 when divided by 97, per ISO 7064. Each failure reports a distinct reason instead of a generic error.
Does a valid IBAN mean the account exists?
No. Passing the format and checksum checks only proves the number is well formed, not that a bank account behind it is open or reachable. An account can be closed, moved, or belong to a different holder. Confirm ownership and existence with the account holder or through the bank before relying on it for a payment.
Can I paste an IBAN with spaces or lowercase letters?
Yes. All whitespace is stripped and letters are uppercased before the checks run, so printed or spaced copies like de89 3704 0044 0532 0130 00 validate identically. Characters outside letters and digits (dashes, dots, slashes) are not part of the IBAN format and produce a bad characters error.
Why do IBAN lengths differ between countries?
An IBAN is a country code plus two check digits plus a national BBAN whose format each country defines, so the total length is set per country in the ISO 13616 registry: 22 characters for Germany and the UK, 27 for France, 15 for Norway. This validator enforces the exact registered length for the country code you enter.
Use IBAN Validator now
Runs in your browser. Nothing you type is uploaded.