How does the MOD-97 IBAN checksum work?

Move the first four characters (country code plus the two check digits) to the end, replace each letter with a number where A is 10 through Z is 35, and treat the result as one big integer. The IBAN is valid only if that integer modulo 97 equals 1.

Does a valid IBAN mean the account exists?

No. A valid result confirms the IBAN is structurally correct, has the right length for its country, and passes the MOD-97 checksum. It does not confirm the bank account exists, is open, or belongs to a particular person.

Why does my IBAN fail on length?

Every country has a fixed IBAN length — for example Germany is 22 characters and the UK is 22, while Malta is 31. A length mismatch usually means a missing or extra character. The tool shows the expected length for the detected country.

Which countries are supported?

All 79 countries in the SWIFT IBAN registry, covering the full SEPA zone plus many non-European countries like Saudi Arabia, Brazil, Pakistan, and the UAE.

Is my IBAN sent anywhere?

No. Country lookup, length check, character validation and the MOD-97 maths all run in your browser. Nothing is uploaded, which makes it safe for batch payment validation.

IBAN Multi-Country Validator

An IBAN (International Bank Account Number) encodes a country, two check digits, and a national account number into one string that banks can validate before a transfer leaves the originating system. This free validator checks an IBAN from any of the 79 SWIFT-registered countries — the universal IBAN checker for finance teams, developers, and anyone setting up a payment.

How it works

The validation has three layers, all defined by ISO 13616:

Country and length. The first two letters identify the country. Each country publishes a fixed total IBAN length (Germany 22, France 27, Malta 31, and so on); the tool compares your IBAN’s length to that table.
Character set. Positions 1-2 must be letters, positions 3-4 must be digits (the check digits), and the rest must be letters or digits.
MOD-97 checksum. Move the first four characters to the end, convert each letter to a number (A = 10 … Z = 35), and read the whole thing as one integer. A valid IBAN satisfies integer mod 97 == 1.

Because the integer can be 30+ digits long, the tool computes the remainder iteratively digit by digit, which is exact and avoids floating-point error.

Example and notes

Validate DE89 3704 0044 0532 0130 00. The tool detects Germany, confirms the 22-character length, verifies the character set, rearranges to put DE89 at the end, converts letters to numbers, and computes mod 97 = 1 — so the IBAN is valid.

A valid result means the IBAN is well-formed and checksum-consistent. It does not confirm the account exists or is open, and the internal bank-account portion (the BBAN) is not separately validated against national rules. Everything runs locally, so your IBAN never leaves your device.