What Does Document Number Mean on Form I-9?

The document number on Form I-9 is the unique string of letters or digits printed on whichever identity or work authorization document your new hire hands you, copied exactly as it appears into the “Document Number” field of Section 2. Every acceptable I-9 document uses its own numbering format, so what you record for a U.S. passport looks nothing like what you record for a Social Security card or a green card. The point of the field is traceability: if federal auditors ever review the form, that number lets them tie your entry back to the specific physical document you examined.

A document number identifies the document itself, not always the person holding it. A driver’s license number identifies the license, not the driver’s Social Security number or date of birth. On a Social Security card, the document number and the personal identifier happen to be the same nine digits. Knowing which number the form is asking for on each document type is what prevents the most common transcription errors.

Finding the Number on List A Documents

List A documents prove identity and employment authorization together, so an employee presenting one does not need anything else. Each has its own numbering format.

U.S. passport book. The passport number sits in the upper-right corner of the data page. Newer books use one letter followed by eight numbers, for nine characters total. Older books may show a shorter all-numeric number. Record whichever format is on the passport in front of you.¹
U.S. passport card. The number is printed on the front of the card, usually near the top, and follows the same general format as a passport book number.
Permanent Resident Card (Form I-551). The green card shows two different numbers. The front carries the USCIS number (the A-Number), and the back carries a separate card number of three letters followed by ten digits. The card number on the back is the one that uniquely identifies the physical card.²
Employment Authorization Document (Form I-766). The card number appears on the front and uses the same three-letter, ten-digit format as the green card’s card number.²
Foreign passport with Form I-94. When an employee shows a foreign passport paired with an I-94, the document number you record is the 11-character I-94 admission number. Records issued before May 2019 are all-numeric; newer records use nine digits, one letter, and one final digit. Most travelers no longer receive a paper I-94 and can pull the electronic record from i94.cbp.dhs.gov.³⁴

Finding the Number on List B Documents

List B documents establish identity only. An employee presenting one from List B also has to present a List C document to prove work authorization.

Driver’s license or state-issued ID card. Record the primary identification number assigned by the issuing motor vehicle agency, printed on the front. Length and format vary by state.⁵
School ID card with photograph. Record the student ID number printed on the card. If the card shows no number, enter “N/A.”⁵
U.S. military card. Record the identification number on the front of the card.⁵
Native American tribal document. Record whatever document number appears. Tribal document formats vary, and if no number is printed, enter “N/A.”
Voter registration card. Record the registration or card number, or “N/A” if none is printed.

The N/A rule applies to any List B document: if the document genuinely has no number on it, write “N/A” in the field rather than leaving it blank.

Finding the Number on List C Documents

List C documents prove employment authorization only, and they have to be paired with a List B document unless the employee is presenting a single List A document instead.

Social Security card (unrestricted). The document number is the nine-digit Social Security number printed on the face of the card. On this document the document number and the personal identifier are the same. The card has no expiration, so enter “N/A” in the expiration field. You cannot accept a card that reads “NOT VALID FOR EMPLOYMENT,” “VALID FOR WORK ONLY WITH INS AUTHORIZATION,” or “VALID FOR WORK ONLY WITH DHS AUTHORIZATION.”⁶⁷
Birth certificate. Accept an original or certified copy bearing an official seal from a state, county, or municipal authority. The document number is the registration or certificate number, often printed near a corner or along the border. Birth certificates do not expire, so enter “N/A” in the expiration field.⁷
Certification of Report of Birth (DS-1350, FS-545, FS-240). Record the certificate number printed on the form.
Native American tribal document. Record the document number if one exists; otherwise enter “N/A.”

What to Do When the Document Has No Number

Some acceptable documents genuinely have no printed number. Rather than leaving the field blank, enter “N/A.” A blank field looks like an oversight during an audit, while “N/A” shows you examined the document and confirmed no number was there to record. The same convention handles the expiration date field for documents that never expire, such as Social Security cards and birth certificates.

When the Employee Has a Receipt Instead of the Document

If a new hire has applied to replace a lost, stolen, or damaged document but does not yet have the replacement, you may temporarily accept a receipt for the application. Record the receipt number in the document number field and write “receipt” next to the document title. The receipt is good for 90 days from the date of hire.⁸

Before those 90 days run out, the employee has to present the actual replacement. When they do, cross out the receipt information in Section 2, record the new document’s title, number, and expiration date, and initial and date the change. If they cannot obtain the same replacement, they may present a different acceptable document from the same list, or a List A document in place of a List B or List C receipt.⁸

Fixing a Document Number You Entered Wrong

If you find a mistake in a document number after Section 2 is done, whether during a self-audit or before a government inspection, do not use correction fluid and do not erase. Draw a single line through the incorrect entry, write the correct number nearby, and initial and date the correction.⁹ The same method applies to filling in a field that was left blank.

Section 2 corrections are for the employer or authorized representative only. The employee never touches Section 2. If the error is in Section 1 and the employee is still on staff, the employee makes the correction themselves using the same line-through method. If they have already left, attach a signed and dated note to the form explaining why the correction could not be made by the employee.⁹

What a Wrong or Missing Document Number Can Cost

Failing to properly complete, retain, or produce Forms I-9 for inspection can result in civil fines assessed per form.¹⁰ Under the inflation adjustment effective January 2, 2025, paperwork violations run from $288 to $2,861 per form.¹¹ One missing or wrong document number on one I-9 can draw a fine at the lower end; a pattern of careless recordkeeping across many forms pushes toward the higher end. The government adjusts these amounts each year, so the numbers typically drift upward.

Section 2 has to be completed within three business days of the employee’s first day of work for pay, and only unexpired documents are acceptable at the time of examination.¹²¹³ Get the number off the document, copy it exactly, and the field is done.

1
U.S. Department of State. Information About the Next Generation U.S. Passport
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U.S. Citizenship and Immigration Services. 13.1 List A Documents That Establish Identity and Employment Authorization
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U.S. Customs and Border Protection. Arrival/Departure Forms: I-94 and I-94W
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Homeland Security. I-94/I-95 Frequently Asked Questions
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U.S. Citizenship and Immigration Services. Form I-9 Acceptable Documents
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Social Security Administration. SSA Handbook 101 – Obtaining a Social Security Card
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U.S. Citizenship and Immigration Services. 13.3 List C Documents That Establish Employment Authorization
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U.S. Citizenship and Immigration Services. 4.4 Acceptable Receipts
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U.S. Citizenship and Immigration Services. 9.0 Correcting Errors or Missing Information on Form I-9
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U.S. Citizenship and Immigration Services. 11.8 Penalties for Prohibited Practices
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Federal Register. Civil Monetary Penalty Adjustments for Inflation
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U.S. Citizenship and Immigration Services. Completing Section 2, Employer Review and Attestation
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eCFR. 8 CFR 274a.2 – Verification of Identity and Employment Authorization