Rechnerpilot tool

IBAN checker

Check an IBAN's length, country format and check digits (ISO 13616, Modulo 97) locally in your browser.

Finance

Enter an IBAN to check its format and check digits.

Explanation

How IBAN checker works

The IBAN (International Bank Account Number, ISO 13616) consists of a two-character country code, two-digit check digits and the country-specific BBAN. Its length is defined per country (Germany: 22 characters).

The check digits are based on ISO 7064 (Modulo-97-10): the first four characters are moved to the end, letters are replaced by numbers (A=10 … Z=35) and the resulting large number is computed modulo 97. The check digits are correct only if the result is 1. This reliably detects typos and transposed digits.

Limitations of this tool

Pure format check — no confirmation that an account exists.
No check of bank code/BIC assignment or account holder.
Unknown country codes are reported instead of checked.

Sources

ISO 13616-1: Financial services — International bank account number (IBAN).
ISO 7064: Check character systems (Modulo 97-10).
SWIFT IBAN Registry, Release 102 (June 2026): all 89 country structures and lengths; verified on 2026-09-07.
SEPA membership and political payment restrictions do not affect the formal IBAN check.

Practice

Practical examples

German IBAN

DE-IBANs have 22 characters; the check digits are verified against the rest of the IBAN using Modulo-97.

Formatting

Spaces and lowercase letters are automatically normalized and displayed in groups of four.

Error detection

A single transposed digit causes the Modulo-97 check to fail and is detected.

FAQ

Frequently asked questions

What does this tool check?

It checks the country-specific sequence of letters and digits, the length and the check digits according to ISO 13616 (Modulo-97 method, ISO 7064). It does not check whether the account actually exists or can be reached for a transfer.

Does "valid" mean that the account exists?

No. A formally valid IBAN merely satisfies the format and the check digits. Whether an account actually exists or is active can only be determined by the bank.

Is my data transmitted?

No. The check is performed entirely locally in the browser. The IBAN is not sent to a server or stored.

How does the Modulo-97 check work?

The first four characters (country code and check digits) are moved to the end, letters are replaced by numbers (A=10 … Z=35) and the resulting number is computed modulo 97. The result must be 1.

Which countries are supported?

All countries with an entry in the official IBAN registry (SWIFT). For unknown country codes, a notice is shown instead of a check-digit verification.

Tips

Good to know

Formally valid ≠ account exists. The check does not replace a bank query.
Spaces may be included and are removed automatically.
A single swapped value causes the check digits to fail.

Related calculators