Germany IBAN validator

A German IBAN replaces the old Bankleitzahl (BLZ) and Kontonummer pair German banks used before SEPA — but it doesn’t discard them, it concatenates them: “DE”, two check digits, the 8-digit BLZ, then a 10-digit account number, with no spaces in the machine-readable form. Because German domestic account numbers were traditionally shorter than 10 digits, the IBAN pads the account block with leading zeros to fill it — a 9-digit Kontonummer becomes a 10-digit block inside the IBAN, and that’s expected, not an error. Anyone paying a German supplier, setting up a SEPA direct debit, or receiving a salary or invoice payment from Germany needs the full 22-character IBAN, which is printed on statements and online banking alongside the older BLZ/Kontonummer pair.

How this validator works

This tool checks the “DE” prefix, confirms the BLZ block is 8 digits and the account block is 10 digits, then runs the real mod-97 checksum (ISO 7064) German banks use to generate valid IBANs — entirely in your browser, with no signup and nothing sent to a server. The result appears the moment you stop typing.

What a pass doesn’t tell you

A pass confirms the IBAN is correctly formed and internally consistent — not that the account is open, active, or belongs to the payee you expect. This tool doesn’t look up the bank name behind a BLZ or contact any bank or clearing system; it’s a pure client-side structure and checksum check. If an IBAN copied from an invoice fails, check first for a dropped leading zero in the account block or a transposed digit in the BLZ — both are common causes of an otherwise-plausible German IBAN failing the checksum.

Scope: this page and tool cover German IBAN structure and mod-97 checksum validation only — not SEPA payment processing, BLZ-to-bank-name lookup, or confirming an account is active, none of which a client-side check can tell you. Use this validator to catch a typo before a transfer fails; use your bank to confirm the account itself.

Content last reviewed 2026-07-07.