How long is a Belgian IBAN?

A Belgian IBAN is exactly 16 characters — BE, two IBAN check digits, a 3-digit bank code, a 7-digit account number and a 2-digit national check. The BBAN is 12 digits.

What is the Belgian national check?

It is a self-contained check inside the BBAN. The last 2 digits equal the first 10 BBAN digits taken modulo 97, where a remainder of 0 is written as 97.

Can an IBAN pass MOD-97 but fail the national check?

Yes, though it is rare. The two checks are computed differently, so this tool runs both and reports each result separately.

Does this tool transmit my IBAN?

No. Both checks run locally in your browser with JavaScript. Your IBAN never leaves your device.

Belgium IBAN Validator

Validate a Belgian IBAN in your browser

A Belgian IBAN is the 16-character account identifier used for Bancontact and SEPA payments in Belgium. It is notable because the national check digits are baked directly into the BBAN, so a Belgian account number is self-validating even before the IBAN layer. This tool verifies both, entirely on your device.

How it works

The Belgian IBAN layout is BE + 2 IBAN check digits + 3-digit bank code + 7-digit account + 2-digit national check (the last three together form the 12-digit BBAN).

The international checksum is ISO 7064 MOD-97-10: rotate the first four characters to the end, expand letters to digits, and require the value modulo 97 to equal 1.

The national check is computed from the BBAN itself:

take the first 10 BBAN digits (bank + account) as a number
remainder = that number mod 97
if remainder == 0 -> 97
the last 2 BBAN digits must equal this remainder

The tool recomputes the expected two digits and compares them with those in the IBAN.

Example and notes

The sample IBAN BE68 5390 0754 7034 has bank code 539, account 0075470, and national check 34. Here the first ten BBAN digits modulo 97 give 34, so the check matches. Because the national check lives inside the account number, Belgian banks can spot many typos before the IBAN checksum even runs. A valid result confirms structure and both checks — not that the account is open.