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IBAN validator
Check whether an IBAN is structurally valid using its ISO 13616 mod-97 checksum. Confirms format and check digits — not whether the account exists.
Input
IBAN check
—Paste an IBAN to verify its mod-97 check digits.
A free IBAN validator that checks an International Bank Account Number against the ISO 13616 mod-97 checksum and the expected length and character pattern for its country. Paste any IBAN and get an instant pass/fail result — everything runs locally in your browser, nothing is transmitted.
How to validate an IBAN
- Paste or type the IBAN into the input field — spaces and uppercase/lowercase are handled automatically.
- The validator identifies the country from the two-letter prefix and checks the expected BBAN length.
- The mod-97 checksum is computed; a result of 1 means the number is structurally valid.
- The result shows whether the IBAN passed or the specific reason it failed.
What the mod-97 check confirms — and what it does not
ISO 13616 mod-97 validation confirms two things: the country prefix and BBAN length are consistent with the standard, and the two check digits are correctly computed from the account number. It does not confirm that the bank or branch exists, that the account is open or active, or that funds can be transferred to it. A structurally valid IBAN can still be rejected by a bank if the underlying account does not exist.
Common reasons an IBAN fails
- Wrong length for the country — each country's IBAN has a fixed total character count.
- Incorrect check digits — even a single transposed digit will change the mod-97 result.
- Invalid characters — BBANs use only digits or alphanumeric characters depending on the country.
- Unknown or unsupported country code prefix.
Frequently asked questions
Does a valid IBAN mean the bank account exists?
No. The validator confirms the format and checksum are correct per ISO 13616. Whether the underlying bank account is open, active, or able to receive funds requires a live bank lookup.
How does IBAN mod-97 validation work?
Move the first 4 characters to the end, replace each letter with its two-digit number (A=10, Z=35), then check that the resulting integer mod 97 equals 1. Any other value means the IBAN is invalid.
Does this validator store the IBANs I enter?
No. Validation runs entirely in your browser using JavaScript. No data is sent to any server, and nothing is logged or stored.
Which countries does the IBAN validator support?
The validator recognizes the standard country codes and BBAN lengths defined in the ISO 13616 registry, covering all European and many Middle Eastern and North African countries that use the IBAN format.