Toolrack

IBAN Validator

Spaces are ignored. Nothing is sent anywhere.
Country—
Check digits—
Length—
Bank code—
—

Checked entirely in your browser. The account number never leaves your device and is not stored.

Check an IBAN's structure and checksum using the official mod-97 algorithm, and see which country and bank code it encodes. Validation happens in your browser — the number is never transmitted.

How the mod-97 check works

The algorithm is defined by ISO 7064 and is the same one used for VAT numbers across Europe:

  1. Strip spaces and uppercase everything.
  2. Move the first four characters — country code and check digits — to the end.
  3. Replace each letter with a number: A becomes 10, B becomes 11, through to Z as 35.
  4. Treat the result as one enormous integer and take it modulo 97. A valid IBAN gives exactly 1.

Because the number can run to fifty digits, it cannot be held in a normal floating-point value. The remainder is computed piece by piece instead, which is what the code on this page does.

What it does and does not prove

QuestionCan validation answer it?
Is the format right for this country?Yes
Was a digit mistyped?Yes — almost always caught
Does this account exist?No
Does it belong to the named person?No
Is the account open and able to receive funds?No

For payments that matter, banks increasingly offer confirmation-of-payee checks that compare the account holder's name before the transfer completes. A checksum is a typo filter, not a fraud control — treat it that way.

Frequently asked questions

Does a valid IBAN mean the account exists?

No, and this is the most important thing to understand about IBAN validation. The check confirms the number is internally consistent — correct length for its country and a matching checksum. It cannot tell you the account is open, belongs to who you think, or has ever existed. Only the receiving bank knows that.

What does the checksum actually catch?

Typing errors. The mod-97 algorithm detects every single-digit mistake, every transposition of two adjacent characters, and the overwhelming majority of other slips. That is exactly what it was designed for — stopping a mistyped digit before the transfer leaves, not verifying identity.

Why do IBANs have different lengths?

Each country defines its own format on top of the common prefix. Norway uses 15 characters, Azerbaijan and Germany 28 and 22 respectively, and Malta 31. Only the first four characters are standard everywhere: two letters for the country and two check digits. The rest is the national account structure.

Should I include spaces?

It makes no difference here — spaces are stripped before checking. The convention is to print IBANs in groups of four for readability and to store them without spaces. Never store the formatted version in a database; strip and uppercase it on the way in.

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