German IBAN Calculator – Bank Code + Account Number to IBAN

How it works

The German IBAN is assembled from three parts and a two-digit checksum:

• •Country code — always DE for Germany.
• •Bank code (BLZ) — the 8-digit Bankleitzahl of your bank or branch.
• •Account number — up to 10 digits, left-padded with zeros to a fixed length of 10.
• •Check digits — two digits computed from the rest of the IBAN with MOD-97 (ISO 7064), so a single typo is caught.

Honest limits: this calculator implements only the public standard formula from the Bundesbank BLZ dataset. It cannot apply the bank-specific IBAN conversion rules from the Bundesbank rule file (which requires registered access). A few banks issue IBANs that deviate from the standard formula, so treat the result as a strong guide — not a guarantee — and confirm it with your bank.

Worked example

Using the German example from this site’s country registry, the BLZ and account number produce DE89 3704 0044 0532 0130 00 with the standard formula. Read its parts from left to right:

Country code

DE

Check digits

89

BLZ (8 digits)

37040044

Account number (10 digits)

0532013000

Account numbers shorter than 10 digits are left-padded with zeros. This is a worked example of the calculation, not confirmation that an account exists.

Bank codes (BLZ) of major German banks

Source: this site’s bank registry, derived from the Deutsche Bundesbank bank code directory; one bank can have several BLZs and BICs, so use the codes in the account holder’s own documents.

Why some banks use account-number rules

Some German banks use bank-specific IBAN conversion rules, so the standard formula can differ from the IBAN issued for an account. This calculator uses the public BLZ dataset and does not apply those additional conversion rules. The registry’s domestic account-number check method is metadata, not an IBAN conversion algorithm. Compare a calculated result with your bank statement or online banking, and ask your bank if they differ. If you also need to check a bank identifier, use the SWIFT/BIC checker.