Códigos OCR del D.N.I. Español play online

DISCLAIMER: This app is not associated with any government entity.

The Spanish National Identity Document (DNI) is a credit card-sized document issued by the Ministry of the Interior through the National Police, which certifies the identity and personal data of its holder, as well as the holder's Spanish nationality.

At the bottom of the back of the DNI, a series of OCR-B characters appear intended to be machine read according to ICAO regulations for documents (Doc 9303 - Machine readable travel documents, Part 3):
https://www.icao.int/publications/Documents/9303_p3_cons_es.pdf

These characters correspond to the data that appears on the front, such as the support number, the dates of birth and validity of the document, the name and surname or the DNI number itself.

Between these OCR characters 4 control numbers appear (indicated in red or green in the application).
One of them is the famous solitary number at the end of the second line.

This application calculates these numbers based on the data entered, thus demonstrating that they do not correspond to what certain urban legends say.

Don't hesitate to try it.