BLZ to IBAN Converter
Enter a German Bankleitzahl (BLZ) and Kontonummer to generate a valid DE IBAN instantly. Free, no registration required.
What Is a BLZ (Bankleitzahl)?
The Bankleitzahl (BLZ) is Germany's 8-digit domestic bank routing code, maintained by the Deutsche Bundesbank. Every branch of every German bank has a unique BLZ. Before the IBAN era, German payments used BLZ + Kontonummer for all domestic transfers.
The BLZ is structured in three parts: the first digit identifies the clearing region (1 = Berlin, 2 = Hamburg/North, 3 = Düsseldorf/Hanover, 4 = Cologne, 5 = Frankfurt, 6 = Stuttgart, 7 = Munich, 8 = Nuremberg), the next three digits identify the banking group, and the final four digits identify the specific branch.
What Is a Kontonummer?
The Kontonummer (account number) is the individual account identifier within a German bank. Kontonummern are up to 10 digits long. When constructing an IBAN, shorter Kontonummern are padded with leading zeros to reach exactly 10 digits.
For example, a Kontonummer of 532013000 (9 digits) becomes 0532013000 in the IBAN — and the resulting IBAN is DE89 3704 0044 0532 0130 00.
German IBAN Format
A German IBAN is always 22 characters and contains:
DE kk BBBBBBBB KKKKKKKKKK
DE — country code (Deutschland)
kk — 2 check digits (MOD-97)
BBBBBBBB — 8-digit BLZ (Bankleitzahl)
KKKKKKKKKK — 10-digit Kontonummer (zero-padded)Example: DE89 3704 0044 0532 0130 00
- DE — Deutschland (Germany)
- 89 — check digits
- 37040044 — BLZ (Deutsche Bank Frankfurt)
- 0532013000 — Kontonummer (zero-padded)
Why Do You Need an IBAN Instead of BLZ + Kontonummer?
Since 1 February 2014, SEPA regulation mandates that all domestic and cross-border euro transfers within the SEPA zone use IBANs. German banks no longer accept BLZ + Kontonummer as a payment destination — the IBAN is the only accepted format for credit transfers and direct debits.
While your bank may still display your BLZ and Kontonummer for reference, any payment instruction must use the IBAN. For international transfers outside SEPA (e.g. USD wire transfers), you also need the bank's BIC/SWIFT code. Look up the BIC for any German bank using the ibanchecker.cash SWIFT directory.
Once you have generated a DE IBAN above, you can validate it with the ibanchecker.cash IBAN checker to confirm the BLZ mapping, check digit integrity, and bank name.
Last updated: June 2026