Form N-400 (Application for Naturalization)

What Form N-400 is

Form N-400 is the only application a lawful permanent resident files to become a U.S. citizen. It is published by USCIS at uscis.gov/n-400. Naturalization is the final step in most family-based and employment-based immigrant pathways. It transforms an LPR into a citizen with full constitutional rights, voting rights, and U.S. passport eligibility.

Eligibility for N-400

To file Form N-400, the applicant must meet all of the following requirements under INA section 316 (or, for spouses of U.S. citizens, INA section 319):

Continuous residence and physical presence

• 5-year rule: 5 years as a lawful permanent resident, with at least 30 months of physical presence in the U.S. during those 5 years.
• 3-year rule for spouses of U.S. citizens: 3 years as an LPR, married to and living with a U.S. citizen spouse for the 3 years, with at least 18 months of physical presence.
• Military exceptions: Active-duty service members under INA section 328 (1 year of military service) or 329 (service during designated periods of hostilities) have reduced or waived periods.

The 90-day early filing window

Under 8 CFR section 334.2(b), applicants can file Form N-400 up to 90 days before their eligibility date. Filing early lets the application sit in USCIS processing while the applicant completes their last 3 months of LPR residency, accelerating the path to citizenship. The applicant must still meet all requirements at the time of the actual interview.

State or USCIS district residence

The applicant must have resided in the state or USCIS district where they file for at least 3 months immediately before filing. This 3-month rule applies to the state and district, not just the city.

Good moral character

The applicant must have demonstrated good moral character during the statutory period (5 years or 3 years). Convictions, arrests, tax violations, certain immigration violations, and other conduct can affect this finding. Some conduct is a permanent bar (murder, aggravated felonies); other conduct is reviewed under a totality-of-circumstances test.

Attachment to the Constitution

The applicant must be attached to the principles of the U.S. Constitution and well-disposed to the good order and happiness of the United States. This is the legal foundation for the Oath of Allegiance.

English and civics ability

The applicant must be able to read, write, and speak English; and demonstrate basic knowledge of U.S. history and government. Specific exemptions apply for older or disabled applicants:

• 50/20 exemption: Age 50 or older with 20 years as an LPR. Exempt from the English test only.
• 55/15 exemption: Age 55 or older with 15 years as an LPR. Exempt from the English test only.
• 65/20 exemption: Age 65 or older with 20 years as an LPR. Exempt from the English test and uses a simplified 20-question civics list.
• Disability waiver (Form N-648): Medical certification waives the English and civics tests for applicants with qualifying physical or mental impairments.

Filing fee in 2026

The 2026 N-400 filing fee is $760 for paper filing and $710 for online filing. The fee includes biometrics services. Three groups can request a fee waiver using Form I-912:

• Applicants on a federal, state, local, or tribal means-tested public benefit (Medicaid, SNAP, TANF, SSI, etc.).
• Applicants whose household income is at or below 150% of the federal poverty guidelines.
• Applicants demonstrating financial hardship (catastrophic medical bills, recent unemployment, eviction).

See our deep guide on the N-400 Fee Waiver for the full eligibility analysis and how to file Form I-912.

Active-duty military and certain veterans pay no fee at all under INA sections 328 and 329. They file Form N-400 with Form N-426 (Request for Certification of Military or Naval Service).

The N-400 process

1. File Form N-400. Online through my.uscis.gov or by paper to the appropriate USCIS lockbox.
2. Biometrics appointment. Scheduled 4 to 10 weeks after filing at a local Application Support Center. Fingerprints, photo, signature. Applicants 75 or older are exempt from biometrics.
3. Naturalization interview. Scheduled at a USCIS field office, typically 8 to 14 months after filing. Includes the English and civics tests and a review of the N-400 contents.
4. Decision. USCIS typically issues a decision at the interview. Possible outcomes: granted (the applicant attends the Oath); continued (additional documentation or testing needed); denied.
5. Oath of Allegiance. Scheduled within a few weeks of approval. Some field offices conduct the oath the same day as the interview. The applicant becomes a U.S. citizen upon taking the oath.

The four tests at the interview

English speaking

The officer evaluates the applicant's spoken English during the routine conversation that runs the N-400 review. The officer asks about the N-400 answers, daily activities, and basic biographical information. The standard is everyday English ability, not perfect grammar.

English reading

The applicant reads one sentence from a USCIS-provided list. The applicant has up to three tries to read one sentence correctly.

English writing

The applicant writes one sentence dictated by the officer. The applicant has up to three tries to write one sentence correctly.

Civics

The applicant answers questions about U.S. history and government from the USCIS list of 100 civics questions. The officer asks 10 questions, and the applicant must answer 6 of 10 correctly. The 65/20 exemption (age 65+ with 20+ years as LPR) reduces the list to 20 questions, with 6 of 10 still required.

See our N-400 Civics Test 2026 guide for the full study list and exam tips, and our N-400 Interview Preparation guide for the broader interview strategy.

What documents to bring to the interview

• The interview appointment notice (Form I-797C).
• Green card (Form I-551) and government-issued photo ID.
• Passport(s) from all countries, including expired ones used during the LPR period.
• All travel records showing trips outside the U.S. since becoming an LPR.
• Tax returns or transcripts for the past 5 years (3 years for spouses of U.S. citizens).
• Certified copies of any arrest, conviction, or court records, even if minor, including dismissals.
• Marriage certificates and divorce decrees for current and all prior marriages.
• Children's birth certificates if applicable.
• Form I-864 affidavit of support records if the applicant is a sponsored relative.
• Selective Service registration evidence for male applicants who entered the U.S. before age 26 (and were under 26 when becoming LPRs).

The Oath of Allegiance

The Oath of Allegiance is the final step. The applicant attends a ceremony, typically in a federal courthouse, at a USCIS field office, or at a community location during designated naturalization events. The applicant recites the oath, surrenders the green card, and receives a Certificate of Naturalization. From that moment forward, the applicant is a U.S. citizen.

After the oath

• Apply for a U.S. passport. The Certificate of Naturalization is the foundational document.
• Update Social Security records. The SSA needs to update from non-citizen to citizen for benefits records.
• Register to vote. Federal voter registration is available immediately.
• Petition for relatives. The new citizen can immediately file Form I-130 for parents, siblings, and married children (categories not available to LPRs).
• Update other records. Driver's license, bank accounts, professional licenses, etc.

Common N-400 problems

• Insufficient continuous residence. Trips abroad longer than 6 months can break continuous residence; trips longer than 1 year almost certainly do.
• Insufficient physical presence. The 30-month / 18-month requirement is strict; tally trips carefully from green card date to filing date.
• Tax issues. Failing to file tax returns, owing back taxes, or filing as a non-resident all raise good moral character concerns.
• Selective Service registration. Male applicants who failed to register can have good moral character issues, particularly if the failure was after age 26.
• Criminal history. Even minor arrests require explanation. Some convictions permanently bar naturalization.
• Marriage timing for the 3-year rule. The 3-year continuous-marriage requirement is strict and must continue through the date of the interview.

Frequently asked questions

Go deeper

For deep guides on the N-400 process, see our N-400 Civics Test 2026, N-400 Interview Preparation, and N-400 Fee Waiver cluster guides, plus the Naturalization pillar overview. For the underlying LPR status, see our Lawful Permanent Resident glossary entry. Return to the Immigration Glossary hub for other terms.