UsefulTab
IBAN Validator
Check an IBAN with the MOD-97 checksum.
Paste an IBAN to validate it
Enter an International Bank Account Number and see whether its ISO 7064 MOD-97 checksum passes, which country it belongs to, and its check digits and BBAN — all computed in your browser.
Runs entirely in your browserValidate an IBAN locally
An IBAN (International Bank Account Number) begins with a two-letter country code and two check digits, followed by the country-specific BBAN. This tool verifies it the way a bank's software does: it moves the first four characters to the end, maps each letter to a number (A=10 … Z=35), and checks that the whole value is congruent to 1 modulo 97 — the ISO 7064 MOD-97-10 scheme. It also looks up the country from the leading code and confirms the length matches that country's fixed IBAN length, so a mistyped or truncated number is caught. Everything runs in your browser, so the account number is never uploaded. A passing checksum means the number is well-formed — it does not confirm the account actually exists at the bank.
Common questions
What does the MOD-97 check actually prove?
It proves the IBAN is internally consistent — the check digits mathematically match the rest of the number under the ISO 7064 MOD-97-10 scheme, so a single mistyped or transposed character is almost always caught. It does not prove the account exists or is open; only the issuing bank can confirm that.
Which countries are supported?
A built-in table of about 35 common IBAN countries — the full SEPA zone plus a few widely used non-SEPA ones — covering the country name and the exact expected IBAN length. The MOD-97 checksum itself works for any IBAN; for a country outside the table you still get the checksum result but a note that the length could not be confirmed.
Is my IBAN uploaded anywhere?
No. The IBAN is validated entirely in your browser with JavaScript. Nothing is sent to a server, which is why the tool keeps working offline once the page has loaded.
What is the BBAN?
The BBAN (Basic Bank Account Number) is everything after the country code and the two check digits — the bank and branch identifiers plus the account number, in that country's own format. The tool shows it separately so you can read it off at a glance.
Why does it group the IBAN in blocks of four?
Printing and reading an IBAN in four-character groups is the convention on bank statements and invoices and makes transcription errors easier to spot. The grouped form is shown and can be copied with one click.