IBAN validator
Three-layer validation: country format and length, international mod-97 check digits, and the domestic bank checksum for countries that define one. Instant, as you type, entirely in your browser.
Spaces and hyphens are fine — checked instantly as you type, only in your browser.
Paste up to a few hundred lines. Nothing is uploaded — the whole list is validated locally.
How to read the result
A failing IBAN tells you which layer failed. A length or format error means the number does not match the country's registered pattern - usually a missing or extra character, or a country code typo. A check-digit error means every position looks plausible but the mod-97 arithmetic does not add up, which almost always indicates a single mistyped or swapped character. A national checksum error is specific to countries like France, Spain, Poland or Hungary, whose domestic account numbers carry their own internal check digit; this layer catches errors that even the international check digits occasionally miss.
A passing IBAN is shown broken into colour-coded segments so you can see the bank code and account portion at a glance and compare them with your source document. Remember the limit of any structural check: it cannot tell you whether the account is open, active, or owned by the person you think. For that, EU banks provide Verification of Payee - read our guide on what it checks and why it matters since October 2025.
Checking a whole list? Switch to the Batch tab and paste one IBAN per line - useful for vetting supplier master data or migration exports. The list is processed locally; it is never uploaded.
Frequently asked questions
What is the difference between an IBAN checker and an IBAN calculator?
A checker verifies an IBAN you already have; a calculator builds the IBAN from a domestic account number. Both are on this site and both run only in your browser.
Why does my IBAN fail with a "check digits" error?
The two digits after the country code are recomputed from the whole number with the mod-97 algorithm. If they do not match, at least one character somewhere in the IBAN was mistyped. Compare the number character by character with the source document.
Does a green result guarantee my transfer will arrive?
No. It guarantees the number is structurally correct, so it will not be rejected for format reasons. Whether the account exists and belongs to the right person is checked by your bank through Verification of Payee.