IBAN Validator
Calculator
IBAN Checker
Check whether an IBAN is valid: format and check digits
The check verifies the format, the length by country and the check digits (MOD-97, ISO 13616). It does not confirm that the account actually exists or that it is active.
More Details
Online IBAN check: how it works
This free tool checks whether an IBAN is formally correct. The check runs entirely in your browser and analyses three aspects: the format (2 country letters + 2 check digits), the expected length for that country and the check digits using the MOD-97 algorithm defined by the international standard ISO 13616. For Italian IBANs it also shows the breakdown into CIN, ABI, CAB and account number.
Important: a formally valid IBAN does not guarantee that the account really exists or that it is active. The check catches the most common typing errors (a wrong digit, missing characters); it does not replace confirmation from the bank.
How an Italian IBAN is structured
The Italian IBAN is made up of 27 characters with this structure:
| Part | Length | Meaning |
|---|---|---|
| IT | 2 letters | Country code (Italy) |
| Check digits | 2 digits | International checksum (MOD-97) |
| CIN | 1 letter | National control character |
| ABI | 5 digits | Bank code |
| CAB | 5 digits | Branch code |
| Account number | 12 characters | Current account |
The total length changes from country to country: for example Germany 22, France 27, Spain 24, United Kingdom 22. The tool knows the lengths of the main European countries and flags any that do not match; country codes not in its list are rejected.
How the check digits are calculated (MOD-97)
To verify an IBAN you move the first four characters (country code + check digits) to the end of the string, convert the letters to numbers (A = 10, B = 11, …, Z = 35) and compute the remainder of the division by 97. If the remainder is 1, the IBAN passes the check. It is the same method banks use to catch transcription errors before processing a transfer.
When it is worth checking an IBAN
Checking an IBAN is useful before sending a large transfer, when adding a new payee, when you receive an IBAN by email or message (where a character can get lost) or when filling in a form for credits such as salary, refunds or pension.
Frequently asked questions
What exactly does this tool check?
It checks the format (country letters and check digits), the expected length for the country and the validity of the check digits using the MOD-97 algorithm (ISO 13616). For Italy it also shows ABI, CAB, CIN and the account number.
Does a "valid" IBAN mean the account exists?
No. The check only confirms that the IBAN is formally correct and free of obvious typing errors. It cannot know whether the account is real, held by a particular person or active: only the bank can confirm that.
What is the CIN of an Italian IBAN?
The CIN (Control Internal Number) is the national control letter that follows the international check digits. It is an additional character used in the Italian banking system to validate the account details.
How many characters does an Italian IBAN have?
The Italian IBAN always has 27 characters. Other countries have different lengths: the length is fixed for each country and the tool verifies it automatically for the main European countries.
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