Germany IBAN Validator

Validate a German IBAN in your browser

A German IBAN (International Bank Account Number) is the 22-character identifier used for every SEPA credit transfer and direct debit in Germany. This tool checks it for correctness without sending anything over the network: the country code, the ISO 7064 MOD-97-10 checksum, and the structure of the BLZ bank code and account number.

How it works

The German IBAN layout is fixed: DE + two check digits + an 8-digit Bankleitzahl (BLZ) + a 10-digit Kontonummer, all digits after the country code. To verify the checksum the tool follows ISO 13616:

1. Strip spaces, uppercase, and confirm the IBAN starts with DE and is 22 characters.
2. Move the first four characters (DE + check digits) to the end of the string.
3. Replace each letter with two digits — A = 10, B = 11, up to Z = 35 — so D becomes 13 and E becomes 14.
4. Compute the resulting big number modulo 97. A valid IBAN gives a remainder of exactly 1.

The MOD-97 step is folded digit-by-digit so it never overflows, matching how banking systems compute it.

Example and notes

The well-known sample IBAN DE89 3704 0044 0532 0130 00 has BLZ 37040044 and account 0532013000, and passes the checksum. A common mistake is dropping a leading zero from the account number — that shortens the IBAN below 22 characters and fails immediately. Note that a passing checksum proves the number is internally consistent, not that the account is active; only the receiving bank can confirm that.