A U.S. passport number has nine characters. If your passport was issued before 2021, those nine characters are all digits. If it was issued after the Next Generation passport rollout, the first character is a letter and the remaining eight are digits. Both formats are valid until the passport itself expires, so how many digits are in a passport number depends on when yours was printed: nine digits on older books, eight digits plus a leading letter on newer ones.1Travel.State.Gov. Information about the Next Generation U.S. Passport
What the Number Looks Like
A Next Generation passport number reads something like A12345678: one letter, then eight numeric digits. The State Department describes passport numbers as randomly assigned and hasn’t publicly explained what the leading letter signifies, so it isn’t a code for the issuing office or passport type.1Travel.State.Gov. Information about the Next Generation U.S. Passport
Older books issued before the changeover still carry a straight nine-digit number with no letters. Some of those passports won’t expire until 2030 or later, which is why both formats are still in circulation.
Where to Find Your Passport Number
Open the book to the biographical data page, the one with your photo, name, and date of birth. The number is printed in the upper right corner.1Travel.State.Gov. Information about the Next Generation U.S. Passport It also appears in the machine-readable zone at the bottom of that page, encoded in the two lines of text and angle brackets that kiosks and border agents scan.
On Next Generation books, the number is also printed at the bottom of each interior page, so that any page swap would leave an obvious mismatch.1Travel.State.Gov. Information about the Next Generation U.S. Passport
The Number Changes Every Time You Renew
Each new passport comes with a new number. The State Department confirms that the number on a renewed passport will be different from the one on the previous book.2U.S. Department of State. Frequently Asked Questions about Passport Services
That matters if you booked flights or applied for a visa under the old number and then renewed before your trip. Most airlines let you update the passport number on a reservation online or at check-in, and any visa or travel authorization tied to the old book should be updated too, since immigration systems match your entry documents against the passport you physically present. If you later need to reference an old number for a past record, keep a copy of the old data page. There is no online portal to look up previous passport numbers; records requests go through the Office of Records Management in writing and take time.
Passport Cards Have Their Own Number
The U.S. also issues passport cards, which are wallet-sized and valid only at land and sea ports of entry between the United States and Canada, Mexico, the Caribbean, and Bermuda. A card cannot be used for international air travel.3eCFR. 22 CFR Part 51 – Passports Cards carry their own nine-character number, separate from the book number. When a form asks for your passport number and you’re flying internationally, it wants the book number.
Typing the Number Without Errors
A single wrong character on an airline booking, visa application, or ESTA can cause an automated check to fail. Electronic visa systems may reject the application outright. Airline bookings often don’t surface the problem until check-in or the gate.
The mistakes to watch for: the letter O confused with the digit 0, and the letter I confused with the digit 1. Since newer U.S. numbers start with a letter, read that first character carefully. When you’re unsure, look at the machine-readable zone at the bottom of the data page. It uses a standardized font designed to remove exactly this ambiguity, and copying from there is the safest way to get all nine characters right.
Other Countries’ Passport Numbers
Nine characters is close to a global norm because the International Civil Aviation Organization’s Doc 9303 standard allocates nine positions for the document number in the machine-readable zone. Countries can fill those positions with letters, digits, or a mix. Chinese and Malaysian passports use a letter followed by eight digits. Philippine passports use two letters and seven digits. Singapore adds a trailing letter as a check character. Thailand uses a two-letter prefix. If a country’s number is shorter than nine characters, placeholder characters fill the rest of the MRZ. So the exact mix of letters and digits varies by issuing country, but the nine-position frame is consistent.