What is the MRZ on a passport?

The machine-readable zone is the two lines of 44 characters printed at the bottom of the data page in OCR-B font. They repeat the document’s key data — type, issuing state, name, number, nationality, date of birth, sex, expiry — in a fixed layout defined by ICAO Doc 9303 so border systems can read it with a scanner. ID cards use three lines of 30 characters (TD1); some other documents use two lines of 36 (TD2).

How is the MRZ check digit calculated?

Each character gets a value (digits as themselves, A = 10 to Z = 35, the filler < as 0), each value is multiplied by a weight that repeats 7, 3, 1, the products are added, and the check digit is the sum modulo 10. The composite check digit runs the same calculation over several fields and their check digits together, so a single wrong character usually fails two checks.

Does a passing check mean the passport is genuine?

No. It means the lines are internally consistent — the check digits match the data they cover. A forged document can have a perfectly valid MRZ, and a genuine one can be reported lost or stolen. Genuineness is established by the chip, the physical security features and the issuing authority, none of which a text check can see.

Why does the checker say a digit fails when the passport is real?

Almost always because one character was misread or mistyped. The usual suspects are 0 and O, 1 and I, 8 and B, 5 and S, or a missing < filler that shifts everything after it. The tool flags letters inside numeric fields and digits inside the name, and when a swap makes the check digit pass it suggests that value. Re-read the printed line character by character against the decoded fields.

What does the tool do with what I paste?

It parses the text in your browser’s memory and shows the result. There is no upload, no account, no storage — not even in the browser’s local storage — and the page makes no network request while you use it. Reload and the lines are gone.

Can it read the MRZ from a photo?

Not this tool: it checks text you type or paste, so you need the lines already as characters. If you have a photo, run it through an OCR step first (the site’s image-to-searchable-PDF tool reads text on-device) and paste the result here; the OCR confusions this checker flags are exactly the ones such a step produces.

Free tool

MRZ checker: verify and decode a passport’s machine-readable zone

Updated October 15, 2026

The machine-readable zone is the two or three lines of capital letters, digits and < at the bottom of a passport or ID card. Paste them here and the checker recomputes each check digit, tells you which one fails, decodes the name, number, dates and nationality, and points out the characters OCR tends to get wrong (0 and O, 1 and I). Nothing you paste leaves the page.

A machine-readable zone has 2 lines of 44 characters on a passport (TD3), 3 lines of 30 on an ID card (TD1) and 2 lines of 36 on a TD2 document. Each date and the document number carry a check digit computed with weights 7, 3, 1; passports and ID cards add a composite check digit over the whole second line (ICAO Doc 9303).

Runs entirely in your browser — your files are never uploaded anywhere.

Step-by-step guide: Documents needed to get a passport: the complete US checklist (first-time, renewal, and kids)

Paste or type the MRZ lines (2 × 44 for a passport, 3 × 30 for an ID card, 2 × 36 for a TD2 document)

Or load an ICAO sample:

Use < for every filler character. Spaces and lower case are corrected for you. Nothing you type leaves this page: there is no upload, no storage, and no network request.

MRZ field positions by format

Positions are counted from 1, as in ICAO Doc 9303. These are the same rows the checker above uses to cut the lines into fields and to decide which characters each check digit covers.

TD3 — passport: 2 lines × 44 characters

Line	Positions	Field	Covered by
1	1–2	Document code	No check digit
1	3–5	Issuing State or organization	No check digit
1	6–44	Name (primary identifier << secondary identifier)	No check digit
2	1–9	Document number	Check digit — document number
2	10	Check digit — document number	(is a check digit)
2	11–13	Nationality	No check digit
2	14–19	Date of birth (YYMMDD)	Check digit — date of birth
2	20	Check digit — date of birth	(is a check digit)
2	21	Sex (M, F or <)	No check digit
2	22–27	Date of expiry (YYMMDD)	Check digit — date of expiry
2	28	Check digit — date of expiry	(is a check digit)
2	29–42	Personal number or other optional data	Check digit — optional data (< or 0 when the field is empty)
2	43	Check digit — optional data (< or 0 when the field is empty)	(is a check digit)
2	44	Composite check digit (positions 1–10, 14–20 and 22–43 of line 2)	(is a check digit)

Source: Doc 9303 Part 4

TD1 — ID card: 3 lines × 30 characters

Line	Positions	Field	Covered by
1	1–2	Document code	No check digit
1	3–5	Issuing State or organization	No check digit
1	6–14	Document number	Check digit — document number (< when the number continues in the optional field)
1	15	Check digit — document number (< when the number continues in the optional field)	(is a check digit)
1	16–30	Optional data (line 1)	Composite check digit only
2	1–6	Date of birth (YYMMDD)	Check digit — date of birth
2	7	Check digit — date of birth	(is a check digit)
2	8	Sex (M, F or <)	No check digit
2	9–14	Date of expiry (YYMMDD)	Check digit — date of expiry
2	15	Check digit — date of expiry	(is a check digit)
2	16–18	Nationality	No check digit
2	19–29	Optional data (line 2)	Composite check digit only
2	30	Composite check digit (line 1 positions 6–30, line 2 positions 1–7, 9–15 and 19–29)	(is a check digit)
3	1–30	Name (primary identifier << secondary identifier) — no check digit	No check digit

Source: Doc 9303 Part 5

TD2 — ID-2 size travel document: 2 lines × 36 characters

Line	Positions	Field	Covered by
1	1–2	Document code	No check digit
1	3–5	Issuing State or organization	No check digit
1	6–36	Name (primary identifier << secondary identifier)	No check digit
2	1–9	Document number	Check digit — document number
2	10	Check digit — document number	(is a check digit)
2	11–13	Nationality	No check digit
2	14–19	Date of birth (YYMMDD)	Check digit — date of birth
2	20	Check digit — date of birth	(is a check digit)
2	21	Sex (M, F or <)	No check digit
2	22–27	Date of expiry (YYMMDD)	Check digit — date of expiry
2	28	Check digit — date of expiry	(is a check digit)
2	29–35	Optional data (no check digit of its own)	Composite check digit only
2	36	Composite check digit (positions 1–10, 14–20 and 22–35 of line 2)	(is a check digit)

Source: Doc 9303 Part 6

MRV-A — full-size visa: 2 lines × 44 characters

Line	Positions	Field	Covered by
1	1–2	Document code (V)	No check digit
1	3–5	Issuing State or organization	No check digit
1	6–44	Name (primary identifier << secondary identifier)	No check digit
2	1–9	Document number	Check digit — document number
2	10	Check digit — document number	(is a check digit)
2	11–13	Nationality	No check digit
2	14–19	Date of birth (YYMMDD)	Check digit — date of birth
2	20	Check digit — date of birth	(is a check digit)
2	21	Sex (M, F or <)	No check digit
2	22–27	Date of expiry (YYMMDD)	Check digit — date of expiry
2	28	Check digit — date of expiry	(is a check digit)
2	29–44	Optional data — no check digit, no composite check digit on visas	No check digit

Source: Doc 9303 Part 7

MRV-B — small visa: 2 lines × 36 characters

Line	Positions	Field	Covered by
1	1–2	Document code (V)	No check digit
1	3–5	Issuing State or organization	No check digit
1	6–36	Name (primary identifier << secondary identifier)	No check digit
2	1–9	Document number	Check digit — document number
2	10	Check digit — document number	(is a check digit)
2	11–13	Nationality	No check digit
2	14–19	Date of birth (YYMMDD)	Check digit — date of birth
2	20	Check digit — date of birth	(is a check digit)
2	21	Sex (M, F or <)	No check digit
2	22–27	Date of expiry (YYMMDD)	Check digit — date of expiry
2	28	Check digit — date of expiry	(is a check digit)
2	29–36	Optional data — no check digit, no composite check digit on visas	No check digit

Source: Doc 9303 Part 7

How the MRZ check digit is calculated

Every character gets a value, each value is multiplied by a weight that repeats 7, 3, 1 from left to right, the products are added, and the check digit is the last digit of the sum (sum modulo 10). The composite check digit runs the same calculation over the data fields and their check digits together, which is why one wrong character usually fails two checks.

Character	Value
0–9	The digit itself (0–9)
A–Z	A = 10, B = 11 … Z = 35
<	0

Worked example on the ICAO sample document number L898902C3: L=21×7, 8=8×3, 9=9×1, 8=8×7, 9=9×3, 0=0×1, 2=2×7, C=12×3, 3=3×1. The products add up to 316; 316 modulo 10 is 6, so the check digit printed after the number is 6.

Source: Doc 9303 Part 3

How to check a passport’s MRZ

Find the MRZ. It is the block of monospaced capitals at the bottom of the passport data page (two lines of 44) or on the back of an ID card (three lines of 30). Each < is a filler, not a typo.
Type or paste the lines. One line per row, exactly as printed. If you are copying from an OCR result, keep the < characters; the tool fixes lower case and stray spaces for you.
Read the verdict. A green verdict means every check digit matches. A red one lists which digit fails and what was expected, so you can find the misread character.
Check the decoded fields. Compare the decoded name, number and dates against the printed data page. A mismatch between the two zones is a reason to look closer.

What it does

Verifies every ICAO Doc 9303 check digit: document number, date of birth, date of expiry, optional data and the composite digit
Handles the three travel-document formats — TD3 passports (2 × 44), TD1 ID cards (3 × 30), TD2 documents (2 × 36) — plus MRV-A and MRV-B visas
Decodes the document code, issuing state, surname and given names, number, nationality, sex, dates and optional data
Flags OCR confusions (0/O, 1/I, 8/B, 5/S) and, where a swap makes the check digit pass, suggests the corrected value
Shows the full field-position table for every format, with a link to the ICAO part that defines it
Runs entirely in your browser: no upload, no storage, no network request — the lines are gone when you reload

What does an MRZ checker actually verify?

It cuts each line into the fields ICAO Doc 9303 defines for that format, recomputes every check digit from the characters it covers, and compares the result with the digit that is printed. A passport (format TD3) has five check digits: document number, date of birth, date of expiry, optional data, and a composite digit over most of the second line. An ID card (TD1) has four, a TD2 document four, and a visa (MRV) three — visas carry no composite digit. The tool then decodes what the fields say: document code, issuing state, surname and given names, nationality, sex and both dates.

Why do passports have check digits at all?

Because the zone is meant to be read by a scanner, and scanners make mistakes. A check digit lets the reading software notice that a 0 came through as an O, or that a line was cut one character short, before the data goes anywhere. It is an integrity check on the text, not a security feature: anyone can compute the digits, and the standard publishes the algorithm. That is also why a passing result says nothing about whether a document is genuine.

Which characters does OCR get wrong?

The OCR-B font used in the MRZ was designed to keep characters apart, but phone cameras, glare and laminate still produce a short list of regular confusions. The tool checks for them in both directions.

Printed	Often read as	Where it shows up
0 (zero)	O	Dates, check digits, document numbers
1	I or L	Dates, check digits
8	B	Dates, numbers
5	S	Dates, numbers
2	Z	Dates, numbers
< (filler)	Dropped, or read as « or K	Names and the padding after every field — a missing filler shifts every later field

A letter inside a numeric field is always wrong, so the tool reports it and tries the digit look-alike; if that makes the check digit pass, it says so. A digit inside the name field is likewise flagged with the letter it probably was.

How are the two-digit years turned into dates?

The MRZ stores dates as YYMMDD with no century. The checker assumes a birth year is in the past (a year up to the current one is read as 20YY, otherwise 19YY) and an expiry year is 20YY unless that would be more than twenty years ahead, in which case it is 19YY. The decoded dates carry a note saying so. For a person born in 1926 or a document that expired decades ago the assumption can be wrong; the raw six characters are shown next to each date so you can judge.

What can’t it tell you?

It cannot see the photo, the chip, the laminate or the watermark, so it cannot say a document is real. It does not know every three-letter code: the list covers ISO 3166 countries and the codes ICAO reserves (D for Germany, GBR and the other British codes, XXA to XXC for stateless persons and refugees, UNO), and an unknown code is shown as is with a note. It reads text, not images, so a photo of a passport has to go through OCR first. And it does not keep anything: the lines live in your browser’s memory for as long as the page is open.