Validate International Bank Account Numbers (IBAN) for format and checksum accuracy.
Enter IBAN with or without spaces
No. The tool verifies structure only: country code, country-specific length, and the checksum. It performs no bank directory lookup and cannot tell you whether the account is open, active, or belongs to the person who gave you the number. Always confirm account existence through the bank itself before transferring money.
It applies the ISO 13616 mod-97 algorithm: the first four characters are moved to the end, every letter is converted to a two-digit number (A is 10, B is 11, and so on), and the resulting number must leave a remainder of exactly 1 when divided by 97. This reliably catches transcription errors such as swapped or mistyped characters.
Specifications for 23 countries are built in, including the United Kingdom (22 characters), Germany (22), France (27), Spain (24), and Norway (15, the shortest). If the number is too short or long for its country, the status explains exactly how many characters that country requires; unrecognized country codes are labeled Unknown Country.
No. Spaces are optional: the input uppercases everything, strips characters that are not letters or digits, and regroups the number into blocks of four as you type. Pressing Enter validates without reaching for the button, and the example buttons load known-valid numbers for the UK, Germany, France, and Spain.
Nowhere. Validation is pure JavaScript running on this page, with no request to any bank, API, or server. Since IBANs identify real accounts, keeping them off the network is the safer default.