Verify the MRZ of a passport: complete guide and verification method

Introduction

The MRZ (Machine Readable Zone) of a passport is a standardized area that enables the automatic reading and verification of the document’s information. It contains the holder’s essential data as well as several security check digits used to detect errors and falsifications.

Used by border authorities, banks, employers, and online platforms as part of identity verification procedures, the MRZ is a key element in detecting document fraud.

This guide explains in detail the structure of a passport MRZ, the information it contains, how check digits work, and the methods used to verify its authenticity.

What is the MRZ of a passport?

The MRZ (Machine Readable Zone) is a machine-readable area defined by the international standard ICAO 9303. This standard ensures that all passports use an identical structure, enabling automatic reading by computer systems.

The MRZ contains the holder’s main identity information, as well as mathematical check digits used to verify the integrity of the data.

Where is the MRZ located on a passport?

The MRZ is located at the bottom of the passport identity page, below the visible information such as the name, photo, and passport number.

It consists of two lines of black characters using the standardized OCR-B font, designed to be easily readable by machines.

How is the passport MRZ structured?

The MRZ of a passport uses the TD3 format, defined by the ICAO 9303 standard.

It consists of:

• two lines,
• a fixed length,
• fields in a strict order,
• check digits.

How many characters are present?

A passport MRZ contains exactly:

• 2 lines
• 44 characters per line
• 88 characters in total

This fixed length allows systems to immediately detect any anomaly or modification.

What information is contained in the first line?

The first line contains:

• the document type (2 characters, P for passport),
• the issuing country (3 characters),
• the holder’s surname (followed by 2 chevrons),
• the holder’s given name(s) (if multiple given names, separated by 1 chevron).

The “<” characters are used as separators and padding characters.

What information is contained in the second line?

The second line contains:

• the passport number (9 characters),
• the passport number check digit (1 character),
• the nationality (3 characters),
• the date of birth (6 characters in YYMMDD format),
• the date of birth check digit (1 character),
• the sex (1 character, M or F),
• the expiration date (6 characters in YYMMDD format),
• the expiration date check digit (1 character),
• the personal number (14 characters, present or not depending on the country),
• the personal number check digit (1 character),
• the final overall check digit (1 character).

How are MRZ security check digits calculated?

MRZ check digits are calculated using an algorithm defined by the ICAO 9303 standard.

This algorithm uses:

• a conversion of letters into numerical values,
• a repeating weighting sequence: 7, 3, 1,
• a modulo 10 calculation.

This mechanism allows the detection of any fraudulent modification or error.

Example

Let’s take as an example the check digit of the date of birth from the specimen above.

The character string to validate is the following: “880504”.

To calculate the check digit, we proceed as follows:

– “8” has a value of 8 and is in the first position, so it must be multiplied by 7:

8 × 7 = 56

– “8” has a value of 8 and is in the second position, so it must be multiplied by 3:

8 × 3 = 24, which is added to the previous 56, resulting in:

24 + 56 = 80

– “0” has a value of 0 and is in the third position, so it must be multiplied by 1:

0 × 1 = 0, which is added to the previous 80, resulting in:

0 + 80 = 80

– 5 × 7 = 35, and 35 + 80 = 115

– 0 × 3 = 0, and 0 + 115 = 115

– 4 × 1 = 4, and 4 + 115 = 119

We therefore obtain a total of 119, from which we extract the modulo 10 (the remainder of the division by 10), which means keeping only the last digit, namely “9”.

Our check digit is therefore valid, as 9 is the digit shown on the document.

Complete MRZ example explained character by character

This MRZ contains all essential passport information:

This is a passport issued by Ireland. The holder’s name is Lauren SULLIVAN. This passport has the number XN5004216. The holder is of Irish nationality, was born on 04/05/1988, and is female. This passport expires on 15/09/2023.

What security checks are present in the MRZ?

The MRZ contains several check digits:

• passport number check digit,
• date of birth check digit,
• expiration date check digit,
• final overall check digit.

These check digits allow verification of the integrity of all data.

How to detect a falsified MRZ?

A falsified MRZ usually presents one or more anomalies:

• incorrect check digits,
• invalid structure,
• incorrect length,
• inconsistencies with visible information.

These anomalies make it possible to detect fraud.

Difference between passport MRZ and ID card MRZ

MRZ formats differ depending on the document type:

• Passport: TD3 format (2 lines, 44 characters)
• ID card: TD1 format (3 lines, 30 characters)

Each format uses a structure adapted to the document.

How to automatically verify the MRZ of a passport?

Manual verification is complex and prone to error. An automated tool allows you to:

• automatically extract the MRZ,
• verify check digits,
• detect inconsistencies,
• detect falsifications.

TrustDocHub allows you to automatically verify a passport MRZ online in just a few seconds.

Why does the MRZ allow fraud detection?

The MRZ is based on an international standardized structure and strict mathematical controls. Any incorrect modification of the information creates detectable inconsistencies.

This makes the MRZ a reliable tool for verifying passport authenticity.

FAQ