Skip to content
TextArray
100% local

IBAN validator

Check IBANs against the official country lengths and the mod-97 checksum — catches typos before a payment, entirely in your browser.

Input
Output
Related tools
Credit card number checkerNumbers
Sum and number statisticsNumbers
Remove extra spacesText cleaning
IBAN validator
Paste one IBAN per line and each comes back checked in three steps: the two-letter country code is looked up in a built-in table of official lengths, the length is compared against that country's exact requirement, and the characters run through the ISO 7064 mod-97 checksum that every real IBAN satisfies. Spaces, dots and lowercase are tolerated, so account numbers copied from invoices, PDFs or banking apps work as they are.
Use it before sending a payment: a single mistyped digit almost always breaks the checksum, so a quick check catches the typo before your bank rejects the transfer — or before the money heads towards an account number that never existed. It is just as useful for cleaning customer or supplier lists: switch Output to valid only or invalid only to split a pasted column into clean and problematic entries, and turn on Remove duplicates to keep each account number once.
Be clear about what a pass means. The tool validates structure and checksum — it cannot confirm that the account exists, is open, or belongs to the person you expect. Only a bank can answer that. A valid result means the IBAN is well-formed, nothing more.
Valid IBANs are printed in the standard groups of four characters (SK89 7500 0000 0000 1234 5671) for readability; switch the formatting option off for a compact, machine-friendly form instead. Everything runs locally in your browser: the IBANs you paste are never sent, logged or stored anywhere, which matters when the list in your clipboard is a real payroll or supplier file.
FAQ
Does a valid result mean the account exists?
No. Valid means the country code is known, the length matches that country and the mod-97 checksum passes — the IBAN is well-formed. Whether the account exists, is open or belongs to the right person can only be confirmed by a bank.
Which countries are supported?
The built-in table covers 35 European countries, including all of the EU/EEA plus Switzerland, the UK, Monaco and San Marino. An IBAN with a country code outside the table is reported as unknown country code rather than guessed at.
Why does my IBAN fail the checksum?
Almost always a typo: one wrong, missing or swapped character changes the mod-97 result. Re-check the number against the original document, especially digit pairs that are easy to transpose.
Can I paste IBANs with spaces or copied from a PDF?
Yes. Spaces and dots inside the number are ignored and lowercase is uppercased, so SK89 7500 0000 0000 1234 5671, sk8975000000000012345671 and a dotted form all validate the same way.
Are the IBANs I paste uploaded anywhere?
No. Validation runs entirely in your browser and nothing is sent, logged or stored. The page makes no network requests with your data — you can even run it offline.