IBAN Validator & Formatter

What this checker actually verifies

An IBAN (International Bank Account Number) is not a random string, it carries a built-in checksum. This tool checks that the country code is a real IBAN country, that the total length matches what that country requires, and that the mod-97 checksum defined by the ISO 13616 standard is correct. It cannot confirm the account actually exists or belongs to anyone, only that the number is internally consistent.

How the checksum works

The 2 check digits right after the country code are computed by moving the first 4 characters (country code and check digits) to the end of the string, converting every letter to a 2-digit number (A = 10 through Z = 35), then treating the whole thing as one large number and checking that it leaves a remainder of exactly 1 when divided by 97. This single arithmetic rule catches the vast majority of typos, including swapped digits and a wrong check digit pair.

Where this tool falls short

A structurally valid IBAN is not proof that the account is open, active, or belongs to the person you expect. Some country codes are rare or newly added to the IBAN registry and may not be recognised here even though they are technically valid. For an actual payment, a UK or EU bank will also run its own verification against the account holder's name before the transfer completes.

IBAN length by country, a few examples