IBAN validator
Is the IBAN right — and why.
Output
Paste or type above to see the result here.
Your files stay on your device
This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
Example
Example: checking a UK IBAN, and catching a typo
GB82 WEST 1234 5698 7654 32 is the sample IBAN used in banking documentation. Paste it as it is — the spaces are fine.
- Move the first four characters to the end: WEST12345698765432GB82.
- Turn the letters into numbers (W = 32, E = 14, S = 28, T = 29, G = 16, B = 11): 3214282912345698765432161182.
- Divide by 97: the remainder is 1, so the check digits 82 fit.
- The parts are split out: bank code WEST, sort code 123456, account number 98765432.
| IBAN typed | Remainder | Result |
|---|---|---|
| GB82 WEST 1234 5698 7654 32 | 1 | Valid |
| GB82 WEST 1234 5698 7654 33 (last digit wrong) | 28 | Not valid |
| GB82 WEST 1234 5698 7654 23 (last two swapped) | 49 | Not valid |
One wrong digit or two swapped ones change the remainder, so the mistake shows before any money is sent. Valid means correctly written — not that the account exists.
How it works
- Paste one IBAN a line — spaces, lower case and an “IBAN” prefix are fine.
- Each is checked for its country’s length and format and for the two check digits.
- The result shows the IBAN in groups of four, the bank and account parts, and the check worked out.
Frequently asked questions
- How is an IBAN checked?
- Move the first four characters to the end, turn letters into numbers (A = 10 … Z = 35), and divide by 97: the remainder must be 1. That catches almost every typing mistake.
- What if the check digits are wrong?
- Then a character somewhere is mistyped. Copy the IBAN again from the original — changing the check digits to fit would only hide the error.
- Which countries are covered?
- All 89 countries and territories in the SWIFT IBAN registry (release 101), each with its length and structure. National check digits are verified too for Spain, Italy, France, Portugal, Belgium and a dozen more.
- Does a valid check digit mean the number exists?
- No — only that it is correctly written. Whether it was issued, and to whom, only the issuing authority can say. The checker never makes up numbers either: it checks the ones you type.
- Where are the sort code and account number in a UK IBAN?
- After GB and the two check digits come four letters for the bank, then the six-digit sort code and the eight-digit account number: GB82 WEST 1234 5698 7654 32 is sort code 12-34-56, account 98765432. Irish IBANs are built the same way, and the checker splits the parts out.
- Can it tell me the bank’s name or BIC?
- No. It shows the bank code inside the IBAN (WEST in the example), but it does not look up the bank’s name or BIC — nothing is looked up online.
- Is anything uploaded?
- No. The check is worked out in your browser, and nothing you type leaves your computer.
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