Learn about the MRZ
Short, plain-language explanations of how the machine readable zone is built, each pointing back to the relevant ICAO Doc 9303 part.
How the check digit works
The 7-3-1 weighted sum modulo 10 that guards every MRZ number and date.
The field map
What each fixed position in the MRZ means.
TD1, TD2, TD3 and visas
The five MRZ shapes and how to tell them apart.
Names in the MRZ
Primary and secondary identifiers, fillers and truncation.
Dates and the pivot year
YYMMDD, validity checks and the two-digit-year problem.
Country and issuing codes
ISO 3166-1 alpha-3 and the Doc 9303 extensions.