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IBAN & VAT Number Validator

Checksum-validate an IBAN (mod-97) or check an EU VAT number's format. Nothing is sent anywhere — useful for validating real account numbers safely.

💡 For when someone sends you a bank account number and you want to check it's typed correctly before you use it.

IBAN validator

EU VAT number format check

How IBAN validation works

An IBAN's last two characters of the country code section encode a checksum computed with the mod-97 algorithm (ISO 7064). This tool rearranges the IBAN, converts letters to numbers (A=10 ... Z=35), and checks that the resulting number mod 97 equals 1 — the same check your bank's systems perform before accepting a transfer.

About the VAT check

This checks that the VAT number matches the expected length and character pattern for its country prefix. It does not confirm the number is actually registered — for that, use the EU's official VIES lookup service.