Which bank does this IBAN belong to?
The bank is written inside the IBAN itself: in a German IBAN, in positions 5 to 12, the Bankleitzahl. The two digits right after DE are check digits and name no bank.
The IBAN is read in your browser. It is not sent anywhere and the API is not called. Only a click opens the page of the bank code, and that code is all its address carries.
Example: DE89 3704 0044 0532 0130 00. The Bankleitzahl is 37040044.
How a German IBAN is built
Always 22 characters, always in this order. The example is the specimen IBAN found in many guides.
- DECountry codeDE for Germany
- 89Check digitsNot a bank: computed from all the other characters
- 3704 0044BankleitzahlThe bank: here Commerzbank, Köln
- 0532 0130 00Account numberTen digits, padded with zeros on the left
Why "DE55" is not a bank
Many people search for "DE55 welche Bank" or "DE87 welche Bank" (which bank is DE55?). The digits after DE are the ISO 13616 check digits: they are computed with the mod 97 method from every other character of the IBAN. Change a single character and the check digits no longer match, so the IBAN shows up as wrong.
That is why any bank can sit behind DE55, just as behind any other check digits. Two customers of the same bank almost always have different check digits, because their account numbers differ.
The bank is told by the Bankleitzahl: the eight digits from position 5. The Deutsche Bundesbank allocates these codes and publishes them in its register, the Bankleitzahlendatei, with the name of the bank, its town and its BIC.
Austria, Switzerland, Liechtenstein
The same idea, other lengths. The box above reads all four countries.
| Country | Length | Bank code | Name | Register |
|---|---|---|---|---|
| DEGermany | 22 | positions 5 to 12 | Bankleitzahl | Deutsche Bundesbank |
| ATAustria | 20 | positions 5 to 9 | Bankleitzahl | Oesterreichische Nationalbank |
| CHSwitzerland | 21 | positions 5 to 9 | IID (clearing number) | SIX BankMaster |
| LILiechtenstein | 21 | positions 5 to 9 | IID (clearing number) | SIX BankMaster |
What the bank code tells you, and what it does not
- Which bank holds the account, with its town and BIC, as the register names them.
- Whether the code is allocated. A code the Bundesbank does not list belongs to no bank.
- Whether the account exists or is open. Only the payee’s bank knows that.
- Whose account it is. Banks compare the name when you pay (Verification of Payee).
Checking from software
If you check many IBANs, in a customer database or before a payment run, the API reads the same register: check digits, bank, BIC, the register’s verdict with its source and edition, in one JSON answer.
- Source: Deutsche Bundesbank, Bankleitzahlendatei, edition September 2026.
- Source: SIX BankMaster, valid from 1 September 2026.
- Austria: the box only reads positions 5 to 9; the page of a code asks the register when it is opened.