IBAN checker & calculator
Validate an IBAN or build one from a domestic account number — for any of the 97 IBAN-registry countries. Everything runs in your browser - what you type is never sent to a server.
Check an IBAN
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.
🔒 Your IBAN never leaves your browser
Convert to IBAN
We'll ask for the details the way your bank shows them.
97 countries, one standard
The complete national account string for the selected country. Spaces and dashes are fine - checked only in your browser.
Supported countries
The ISO code of all 97 IBAN-registry countries - one standard, zero uploads.
What happens when you validate an IBAN
An IBAN (International Bank Account Number, ISO 13616) packs a country code, two check digits and a country-specific domestic account number into a single string of up to 34 characters. This checker first confirms the country code is a real IBAN country and the length matches that country's registered format. It then recomputes the mod-97 check digits, which catch virtually all single typos and most transposed characters. Finally, for countries whose domestic format carries its own internal check digit - such as France, Spain, Belgium, Poland, Norway, Portugal or Hungary - it verifies that national checksum too, a layer many online checkers skip.
Each result explains itself: if the IBAN fails, you see which layer failed and where to look for the typo, with the number broken into colour-coded segments (country, check digits, bank code, branch, account). If it passes, you still get the honest caveat: a formally valid IBAN is not proof that the account exists or belongs to the person you intend to pay. That confirmation is what your bank's Verification of Payee service is for.
Built for privacy by design
An IBAN identifies a bank account, so it deserves the same care as any personal data. This site takes the simplest possible approach: the validation logic (the open-source ibantools library plus country data from the official SWIFT registry) is bundled into the page itself. There is no backend, no API call, no analytics event containing your input. The guides explain how the algorithms work if you want to audit the maths.
Frequently asked questions
Is it safe to type my IBAN here?
Yes. Validation runs entirely in your browser using open-source code; the IBAN is never transmitted, logged or stored. You can verify this yourself: open your browser DevTools Network tab while typing - no request carries the IBAN.
What does this checker actually verify?
Three layers: the country-specific length and character format, the international mod-97 check digits (positions 3-4), and, for countries that have one, the domestic bank check digit inside the account number (France, Spain, Poland, Hungary and others).
If my IBAN is valid, does the account exist?
No. A valid IBAN only means the number is structurally correct. It says nothing about whether the account is open or who owns it. Before sending money, rely on your bank’s Verification of Payee check, which EU banks must offer for euro transfers.
Can I check many IBANs at once?
Yes, use the Batch check tab: paste one IBAN per line and the whole list is validated locally in your browser. There is no upload and no server involved.