How long is a Spanish IBAN?

A Spanish IBAN is exactly 24 characters — ES, two check digits, a 4-digit entity code, a 4-digit office code, two CCC control digits and a 10-digit account number.

What are the CCC control digits?

They are Spain's legacy Código Cuenta Cliente check. The first digit verifies the bank and office; the second verifies the account, each via a weighted mod-11 calculation.

How is each CCC digit computed?

Each block is multiplied by the weights 1,2,4,8,5,10,9,7,3,6, summed, and reduced as 11 minus (sum mod 11), where a result of 10 becomes 1 and 11 becomes 0.

Does this tool send my IBAN anywhere?

No. All validation happens locally in your browser. Nothing is transmitted, stored or logged.

Spain IBAN Validator

Validate a Spanish IBAN in your browser

A Spanish IBAN is the 24-character account identifier behind every SEPA payment and direct debit in Spain. It embeds the country’s older CCC (Código Cuenta Cliente) format, including its two mod-11 control digits, so this tool verifies both the international checksum and the national CCC.

How it works

The Spanish IBAN layout is ES + 2 IBAN check digits + 4-digit entity (banco) + 4-digit office (sucursal) + 2 CCC control digits + 10-digit account.

The international checksum is the standard 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 CCC control digits are two separate weighted mod-11 checks:

weights = 1, 2, 4, 8, 5, 10, 9, 7, 3, 6
D1 over "00" + entity(4) + office(4)   (10 digits)
D2 over the 10-digit account
each: r = 11 - (weighted_sum mod 11); 10 -> 1, 11 -> 0

The tool recomputes both digits and compares them with the pair embedded in the IBAN.

Example and notes

The sample IBAN ES91 2100 0418 4502 0005 1332 has entity 2100, office 0418, CCC 45 and account 0200051332. The first CCC digit is padded with two leading zeros before the entity and office because the weighting table expects a full 10-digit block. A passing result confirms the IBAN’s structure and both checksums — it does not confirm the account is active, which only the bank can verify.