IBAN Validator

Validate an IBAN: country code, expected length, and the mod-97 checksum. Identifies the bank country and shows the IBAN broken into its parts. Browser-only.

How to use the IBAN Validator

Type or paste any IBAN. Spaces are ignored; case is normalized. The validator checks format against the country's expected length and runs the mod-97 checksum (which catches almost any single-digit error).

What IBAN validation actually checks

Validating an IBAN is three checks in one. First the country code must be a real two-letter code with a known IBAN length; a German IBAN that is not 22 characters is wrong before you look further. Second the structure of the BBAN — the account portion — must match that country's pattern. Third, and most useful, the two check digits must satisfy the Mod-97 rule, which catches almost every single mistyped or transposed character.

That checksum is the reason IBANs are robust: a typo in a long account number would otherwise be silent, but Mod-97 turns it into an immediate failure. This validator runs all three checks, normalizes spacing and case, and splits the IBAN into its parts so you can see the country, check digits, and account number separately. To produce valid test IBANs instead, use the IBAN generator.

Common use cases

  • Pre-submit validation — catch a mistyped IBAN before a payment form is sent.
  • Cleaning imported data — check a column of IBANs from a spreadsheet or CSV for bad entries.
  • Support and ops — quickly confirm whether a customer-supplied IBAN is well-formed.
  • Identifying the country — read the country code to see which bank network an IBAN belongs to.
  • Debugging transfers — rule out a malformed IBAN as the cause of a rejected payment.

Frequently asked questions

Does a valid checksum mean the account exists?
No. Mod-97 only proves the IBAN is internally consistent and free of typos. It cannot tell you whether the account is open, funded, or even issued — only the bank can confirm that.

Why does Mod-97 catch so many errors?
Reading the IBAN as a huge number mod 97 is sensitive to almost any change: a single wrong digit or a pair of swapped characters nearly always changes the remainder. That is why it reliably flags the most common kinds of typo.

Are spaces and lower-case letters allowed?
IBANs are often printed in groups of four for readability, and people paste them in mixed case. The validator strips spaces and upper-cases letters before checking, so either form is fine on input.

What is a BBAN?
The Basic Bank Account Number is the country-specific part that follows the check digits — typically a bank code, sometimes a branch code, and the account number. The IBAN wraps it with a country code and checksum.
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