Check an IBAN locally in your browser by length and the modulo-97 check digit - covering 80+ countries, with no upload, even offline.
Running locally on your device ...
Running locally on your device ...
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Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
An IBAN (International Bank Account Number) consists of a 2-letter country code, a 2-digit check number and a country-specific account number (BBAN) - the total length and internal layout are officially fixed per country (ISO 13616). This tool detects the country from its code, checks that country's officially fixed length, and recomputes the check number using the internationally standardized modulo-97 procedure (ISO 7064 MOD 97-10).
The whole check runs entirely locally in your browser in pure JavaScript - the IBAN is not uploaded, not stored, and no foreign library is loaded from a CDN. The length table covers 78 countries that actually use the IBAN - far more than just the EU: including the UK, Switzerland, Norway, Turkey and several Gulf states. You can download the result as a JSON file or read it directly.
An honest note: this is purely a structural and check-digit test, not a request to any bank or registry. An IBAN reported valid can still not exist, be blocked, or belong to someone other than expected - for an actual transfer, your bank's or payment provider's confirmation remains authoritative.
Some online IBAN checkers additionally cross-reference the input against a database - but that requires sending the IBAN to their server, an unnecessary risk for your own account number. This tool checks the length and check digit strictly locally in the browser; the IBAN never leaves your device.
| Input formats | Text input |
|---|---|
| Output format | JSON |
| Batch processing | No |
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: Purely a structural and check-digit test (length + modulo-97), not a request to any bank or registry. A valid IBAN can still not exist, be blocked, or belong to someone else. For an actual transfer, your bank's confirmation remains authoritative.
No. The check runs entirely locally in your browser; the IBAN never leaves your device and is not stored.
No. The tool only checks the length and the check digit - not a lookup against any bank or registry. A mathematically valid IBAN may still never have been issued or may be blocked.
No. The length table covers 78 countries, including the UK, Switzerland, Norway, Turkey and several Gulf states - the IBAN is not an EU-only format.
The internationally standardized check procedure (ISO 7064 MOD 97-10): the country code and check number move to the end, letters convert to numbers, and the resulting large number must leave remainder 1 when divided by 97.
The tool honestly reports "unknown country code" instead of faking a result - not every country uses the IBAN.
Yes, in any current mobile browser just like on desktop - the IBAN stays local.
No, it is completely free, with no account and no limit on the number of checks.
Because many such tools send the IBAN to their server for checking. An IBAN is an account number and therefore personal data - with this tool it stays exclusively on your device.
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