IBAN Validator
Check any IBAN with the official MOD-97 checksum, country length rules and a full bank/account breakdown.
- Country
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- Print format
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- Electronic format
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- Length
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- Check digits
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- SEPA area
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Account structure
| IBAN | Country | Result |
|---|
Type or paste an IBAN above — it is checked as you type.
How it works
An IBAN is validated in three steps, and this checker runs all three as you type. First the country code must be one of the ~85 codes in the official IBAN registry. Second the total length must match that country's fixed length — a German IBAN is always 22 characters, a Dutch one 18, a British one 22. Third the two check digits must satisfy the ISO 7064 MOD-97-10 checksum: the first four characters are moved to the end, every letter is replaced by a number (A = 10 … Z = 35) and the resulting integer must leave a remainder of 1 when divided by 97. If the checksum fails, the tool also tells you which check digits the rest of the number actually implies, so you can spot a transposed pair of digits immediately.
For valid IBANs the account is split into its parts — bank code, branch/sort code, account number and any national check digit — and shown in both the print format (groups of four) and the electronic format (no spaces). Paste several IBANs, one per line, to check a whole list at once and download the results as CSV. Everything runs in your browser in plain JavaScript: no bank details are uploaded, which is exactly what you want from a tool handling account numbers. Note that a valid IBAN only proves the number is well-formed — it cannot tell you whether the account exists or who owns it.
Frequently asked questions
How do I check if an IBAN is valid?
Paste the IBAN into the box — it is checked as you type. The validator confirms the country code exists in the IBAN registry, that the length matches that country's fixed length (22 for Germany, 18 for the Netherlands, 16 for Belgium) and that the two check digits satisfy the ISO 7064 MOD-97-10 checksum. Spaces, dashes and lower case are cleaned up automatically.
What are the IBAN check digits and how are they calculated?
Characters 3 and 4 of every IBAN are check digits that protect against typos. To verify them the first four characters are moved to the end, each letter is replaced by a number (A = 10 up to Z = 35) and the resulting integer must leave a remainder of 1 when divided by 97. When the checksum fails, this tool also shows which check digits the rest of the number implies, so a swapped pair of digits is easy to spot.
Does a valid IBAN mean the bank account exists?
No. A valid IBAN only proves the number is well-formed: right country, right length, correct checksum. It cannot confirm that the account is open or who owns it — only the bank can do that. Since this checker runs entirely in your browser and never uploads anything, it is safe to paste real account numbers, including a whole list for a bulk check with CSV export.