IBAN validator
Check an IBAN with country length and the ISO 13616 MOD-97-10 remainder. Runs locally.
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After IBAN: other identifiers and formats
After using IBAN validator, continue with CUIT/CUIL validator.
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Tool guide
IBAN validator: how it works
Practical information to understand the result and use this tool correctly.
About IBAN validator
The validator strips spaces and hyphens, checks the IBAN pattern, compares length with a country table, then runs the MOD-97-10 remainder. A valid IBAN leaves remainder 1.
It does not confirm that the account exists. Unknown country codes still get a checksum if the string matches the generic pattern.
How to use it
- 1Paste an IBAN. Spaces and hyphens are ignored. Empty input stays unchecked.
- 2Read format, country length, and the MOD-97 remainder. Copy the summary or reset to clear the field.
Frequently asked questions
- Is GB82 WEST 1234 5698 7654 32 valid?
- Yes. Country GB expects 22 characters. After rearranging, the MOD-97-10 remainder is 1.
- Is ES91 2100 0418 4502 0005 1332 valid?
- Yes. Spain expects 24 characters and the checksum remainder is 1. Changing the last digit to 3 fails the remainder.
- Which formula and units are used?
- Move the first four characters to the end, map A–Z to 10–35, and take the number mod 97. Valid means remainder 1. Length is characters after removing spaces.
- What happens with empty input, a short string, or a bad check digit?
- Empty input is not a pass. A string that breaks the pattern fails format. A known country with the wrong length fails before the checksum. A wrong check digit shows a remainder other than 1.