Tools
IBAN checksum
Moves the first four characters to the end, maps letters to digits, and requires remainder 1 modulo 97.
Valid checksum
DE89 3704 0044 0532 0130 00
Checksum valid. Issued in Germany.
A valid checksum is not proof the account is open, or that the holder is who they claim. The first two letters are the issuing country — not the app HQ. IBAN country ≠ HQ.