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Check-digit calculation for account numbers

General information

The validation of account numbers using the check-digit method promotes the smooth and automated settlement of payments. Therefore a payment service provider is obliged to announce the check-digit calculation method for their payment accounts and to use only account numbers for payments which are detected by the reported check-digit calculation method.

Introduction of and amendments to check-digit calculation methods

The payment service provider are allowed to choose which check-digit calculation method they use. The Deutsche Bundesbank issues codes for check-digit calculation methods in accordance with an agreement with the central associations of the banking industry and maintains a list of the check-digit calculation methods used in the banking industry.

If a credit institution selects a procedure which does not yet have a code, the account-holding branch of the Deutsche Bundesbank must be informed, if applicable via its head office or its central association. This information should contain a precise description of the procedure, a sample calculation and both correct and incorrect test account numbers. Please note that a lead time of around six months should be allowed for the introduction or amendment of a check-digit calculation method.

If the description of a check-digit calculation method needs to be changed because, for example, the range of account numbers used is to be extended, the payment service provider using this method must mutually agree this and inform the Deutsche Bundesbank accordingly.

The introduction or amendment of check-digit calculation methods and their validity dates as well as the general overview of the descriptions of the check-digit calculation methods are posted here on the Deutsche Bundesbank's website. Payment service provider will also find this information in publications of their central associations.

Calculating a check digit

Validation of an account number to check that it complies with the general calculation instructions for a given credit institution's account numbers requires the complete account details, the algorithm of the check-digit calculation method (in German only) and the bank sort code file.

The codes for the calculation method used by the various payment service provider appear in field 9 of the bank sort code file. Payment service provider that do not have a (published) check-digit calculation method enter the code »09«.

Please note, however, that positive validation of an account number does not prove that this account actually exists, but merely indicates that this would be a valid account number.

List of the check-digit calculation methods used in the banking industry

For the validation date 4 December 2017 there is no modification of the check-digit calculation methods. The version of September 2017 is still valid.

Enquiries about individual descriptions of check-digit calculation methods

Enquiries about individual descriptions of check-digit calculation methods should be addressed to the payment service provider which use them. However, queries about check-digit calculation methods used by the cooperative payment service provider, which are represented by the Federal Association of People's Banks and Raiffeisen Banks (Bundesverband der Deutschen Volksbanken und Raiffeisenbanken, BVR), should be sent to the this e-mail address.

Please note that e-mail enquiries about bank sort codes and check-digit calculation methods sent to the payment service provider, the BVR or the Bundesbank can be answered only if the enquirer gives his/her full address and telephone number.