IBAN Validator

An IBAN is structured in three parts: a two-letter country code, two check digits, and the BBAN — the Basic Bank Account Number, which is the domestic account identifier formatted to that country's local standard. The whole thing is between 15 and 34 characters depending on the country. Norway is the shortest at 15; Malta tops out at 31. Spaces are allowed in the human-readable printed form but are stripped before any validation or processing. You can paste an IBAN here with or without spaces and the result is the same.

What the MOD-97 algorithm actually does — and what it doesn't

The check digit validation works by rearranging the IBAN: move the first four characters to the end, replace each letter with its numeric equivalent (A=10, B=11 ... Z=35), then compute the whole number modulo 97. If the result is 1, the IBAN passes. This algorithm catches over 99% of single-character transcription errors and all transpositions of adjacent digits — which makes it genuinely useful as a first-pass filter before you attempt an actual bank transfer. What it cannot do is confirm the account exists or belongs to a specific person. A number can pass every structural check and still be unassigned, closed, or belong to someone entirely different. Validation here is about format integrity, not account existence.