ICAO Doc 9303 explained: the 13 parts, the MRZ and the chip

Published 2026-11-13 · By the Koncile team

ICAO Doc 9303 is the international specification for passports, ID cards and visas that machines can read. Its eighth edition (2021) has 13 parts: parts 3 to 7 define the printed data page and the machine readable zone (MRZ), parts 9 to 12 the chip and its certificates, part 13 a signed barcode. To read documents from photos, parts 3, 4 and 5 are the ones that matter.

What ICAO Doc 9303 is, in one paragraph

ICAO Doc 9303, titled Machine Readable Travel Documents, is the specification that every passport, most national ID cards and many visas follow so that a reader anywhere in the world can read them. It is published by the International Civil Aviation Organization (ICAO), the United Nations agency for civil aviation, and the same text is endorsed by ISO and IEC as ISO/IEC 7501. The current version is the eighth edition, published in 2021 and split into 13 parts, with amendments issued up to February 2026. The digital version is free to download from the ICAO website; the ICAO store sells printed copies.

The document fixes two things. First, the printed side: page sizes, where each field sits on the data page, and the machine readable zone (MRZ), the two or three lines of capital letters, digits and chevrons at the bottom. Second, for electronic passports, the contactless chip: what data it stores, how a reader opens it, and how the signature proves the data came from the issuing state. ICAO required its member states to issue only machine readable passports from 1 April 2010, and the last non machine readable passports had to expire by 24 November 2015.

The 13 parts of Doc 9303 and what each one covers

Nobody reads Doc 9303 from cover to cover. Each part answers a different question, and most teams only ever open three or four of them. Titles below come from the ICAO store listing, read on 13 November 2026; the last column says who usually needs the part.

If your job is to read documents from photos or scans, parts 3, 4 and 5 hold almost everything you need, part 6 and part 7 cover the rarer formats, and the chip parts (9 to 12) only matter if you hold the physical document against an NFC reader. The MRZ formats guide compares TD1, TD2, TD3 and the two visa formats character by character.

Which documents follow ICAO 9303

The standard calls all of them machine readable travel documents (MRTDs), even when they are used far from an airport. In practice, a reader built to Doc 9303 meets four families of documents:

• Passports, in the TD3 size, with a 2 line MRZ of 44 characters. Almost every passport in circulation is machine readable, and most now carry a chip as well.
• National identity cards in the TD1 size, with a 3 line MRZ of 30 characters on the back. All EU identity cards issued since August 2021 must follow Doc 9303, under Regulation (EU) 2019/1157.
• Residence permits and other official cards, in TD1 or TD2 size depending on the country.
• Visas and emergency travel documents, covered by parts 7 and 8.

Some documents look official but sit outside the standard. US driver's licenses follow the AAMVA format and its PDF417 barcode, not an MRZ, and several national ID cards, India's Aadhaar card among them, carry no MRZ at all. For those, a reader has to work from the printed text alone.

What the MRZ carries, per Doc 9303

Part 3 sets the rules shared by every format: only the 26 capital letters A to Z, the digits 0 to 9 and the filler character <, printed in the OCR-B typeface inside a reading zone 17 millimetres high. Accents are dropped or transliterated (ä can become AE), a space or hyphen in a name becomes <, and long names are truncated with a defined rule. Dates are written YYMMDD. Part 4 then places each field on the passport. Here is the specimen ICAO uses, for a fictitious citizen of Utopia (UTO):

P<UTOERIKSSON<<ANNA<MARIA<<<<<<<<<<<<<<<<<<<
L898902C36UTO7408122F1204159ZE184226B<<<<<10

Line 1 holds the document code (P for a passport), the issuing state and the name, surname first, separated from the given names by <<. The five check digits are computed with repeating weights of 7, 3 and 1, modulo 10, as described in part 3; the MRZ check digit guide works through the calculation and the common mistakes. A check digit catches a misread character or a typo. It does not prove that a document is genuine: anyone who knows the algorithm can produce a valid line.

What the chip parts add, and why OCR alone cannot cover them

An electronic passport stores a copy of the MRZ (data group DG1) and the holder's face image (DG2) on a contactless chip, sometimes with fingerprints (DG3) and other data groups. Part 11 defines how a reader opens the chip: it derives a key from the document number, date of birth and expiry date read in the MRZ, through Basic Access Control (BAC) or the newer PACE protocol. Part 12 defines the certificates behind passive authentication: each country signs the chip data with a document signer key, itself certified by its country signing certificate authority (CSCA), and ICAO runs a public key directory (PKD) through which states share those certificates.

Chip reading is the strongest check the standard offers, because a forger cannot produce a valid signature without the issuing state's keys. It needs the physical document and an NFC reader. A photo or a scan of the data page, which is what most online onboarding receives, carries the printed page and the MRZ, never the chip. Software working from images can only apply the printed side of Doc 9303: formats, check digits, and the consistency between the MRZ and the visual zone.

Using Doc 9303 when you read documents from images

For a team that extracts data from passports and ID cards, the standard gives a checklist that works without any special hardware:

1. Identify the format from the number and length of MRZ lines: 2 x 44 for a passport or MRV-A visa, 3 x 30 for an ID card, 2 x 36 for TD2 or MRV-B.
2. Parse the fields at their fixed positions, and keep the raw lines with the result so that anyone can check the parsing later.
3. Recompute the check digits and flag any line where one fails; a failure is often a misread 0 and O or 8 and B, not a fake.
4. Compare the MRZ with the printed zone: name, date of birth, document number and expiry should agree. A mismatch is a reason to look closer.
5. Treat the result as a signal, never as proof of authenticity. A well made counterfeit can carry a perfectly valid MRZ.

Koncile, which publishes this site, does this reading in one call: the MRZ lines and parsed fields, the printed fields the MRZ does not carry, and a fraud score from 0 to 100 that is a signal to verify, never an accusation. It does not read the chip, match faces or check liveness, so the protections of parts 9 to 12 stay out of reach, as they do for any image based tool. The MRZ OCR page lists what comes back.

Editions and what is changing

Doc 9303 is revised in editions, with amendments in between. The eighth edition dates from 2021. The ICAO store lists amendments to parts 3, 4, 7, 8, 9, 10, 11, 12 and 13 dated between November 2022 and February 2026, the latest being amendment no. 2 to part 11 (security mechanisms), dated 23 February 2026, and amendment no. 2 to part 8 (emergency travel documents), dated 6 February 2026.

A ninth edition is in preparation, and its most visible change is already decided: a fixed two letter document code at the start of every passport MRZ, such as PP for an ordinary passport, PD for a diplomatic one and PE for an emergency passport, instead of the free second letter states use today. Keesing Platform reported the proposal in August 2025, and a working paper of ICAO's TAG/TRIP group (November 2025) says documents with a one letter code will not be accepted after 1 January 2038. The MRZ structure does not change. Parsers that accept any letter after P keep working; parsers that hard code P< should be checked.

Sources

• ICAO, Doc 9303 Machine Readable Travel Documents, publication page (blocked for robots on 13 November 2026, part titles read on the ICAO store)
• ICAO store, Doc 9303 parts and amendments, read on 13 November 2026
• ICAO store, Doc 9303 part 12, eighth edition 2021, read on 13 November 2026
• ICAO Doc 9303, part 3: specifications common to all MRTDs
• ICAO Doc 9303, part 4: machine readable passports (TD3)
• Regulation (EU) 2019/1157 on the security of identity cards and residence documents
• ICAO TAG/TRIP/5, working paper 30: second letter code for passports (November 2025)
• Keesing Platform, Proposal to standardize machine readable zone passport codes, 12 August 2025, read on 13 November 2026
• Wikipedia, Machine-readable passport, read on 13 November 2026