Online Tool Store
IBAN Validator
Check whether an IBAN has a valid country-specific length and mod-97 checksum, catching typos before you send a payment. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown — spaces are ignored.
How it works
- Paste an IBAN (spaces are fine).
- It's checked against the expected length for its country code.
- A mod-97 checksum confirms whether the IBAN is internally consistent.
The formula
Rearrange the IBAN, convert letters to numbers (A=10, B=11, ... Z=35), then check the remainder:
(rearranged numeric IBAN) mod 97 = 1
FAQ
Does a valid checksum mean the account actually exists?
No — checksum validation only confirms the IBAN is correctly formatted and internally consistent (catching typos). It can't confirm the account is real or open; only your bank can do that.
How does the checksum work?
IBANs use a mod-97 checksum (ISO 7064) — the country code and check digits are moved to the end, letters are converted to numbers, and the whole number must leave a remainder of 1 when divided by 97.
Which countries are supported?
All current IBAN-participating countries, checked against each country's official IBAN length.
Is my IBAN uploaded anywhere?
No — validation happens entirely in your browser.
How we compare
| Feature | Online Tool Store | Bank verification | Manual checksum math |
|---|---|---|---|
| Instant format check | ✓ | ✗ | ✗ |
| Confirms the account is real and open | ✗ | ✓ | ✗ |
IBAN Validator catches typos before you send a payment — it's not a substitute for your bank's own account verification.