Naturalization Eligibility and the N-400

Short answer: To become a U.S. citizen through naturalization, most green card holders must show five years of continuous residence and physical presence as a permanent resident (three years if married to and living with a U.S. citizen spouse), good moral character, basic English ability, knowledge of U.S. civics, and "attachment" to the principles of the Constitution. You prove all of this by filing Form N-400, Application for Naturalization, with U.S. Citizenship and Immigration Services (USCIS), completing biometrics, passing an interview and test, and taking the Oath of Allegiance. Every rule below has exceptions, and fees, forms, and test versions change — always confirm the current details at uscis.gov/n-400 before you file.

Who is generally eligible

You are typically eligible to file Form N-400 if you meet all of the following:

• Age: You are at least 18 years old at the time you file.
• Lawful permanent residence: You have held a green card for at least 5 years, or at least 3 years if you have been married to and living with the same U.S. citizen spouse during that entire period.
• Continuous residence: You have lived continuously in the United States for that 5-year (or 3-year) period. A single trip abroad of one year or more generally breaks continuous residence and can require you to start the clock over (with narrow exceptions, such as certain government or qualifying employment abroad covered by Form N-470). Trips of six months to a year create a rebuttable presumption that you broke continuous residence, which you can overcome with evidence such as proof you kept your job, home, and family ties in the U.S.
• Physical presence: You have actually been present inside the United States for at least half of the statutory period — about 30 months out of 5 years, or about 18 months out of 3 years for spouses of citizens.
• State/USCIS district residence: You have lived for at least the three months immediately before filing in the state or USCIS district where you are applying.
• Good moral character: You have behaved lawfully during the statutory period (and USCIS can look further back). Certain acts create permanent or conditional bars — for example, certain criminal convictions, false claims to U.S. citizenship, unlawful voting, failure to pay owed child support, or fraud. USCIS has emphasized closer scrutiny of these issues in recent policy updates, so disclose your full record honestly; concealment is often worse than the underlying problem.
• English language ability: You can generally read, write, speak, and understand basic English. There are long-standing age/residency exemptions: applicants who are age 50+ with 20 years as a permanent resident, or age 55+ with 15 years as a permanent resident, may take the civics test in their own language. Applicants with a qualifying medical disability may request an exemption from the English and/or civics requirements using Form N-648, completed by a licensed medical professional; USCIS has said it is reviewing these requests more strictly.
• Civics knowledge: You must correctly answer questions about U.S. history and government during your interview.
• Attachment to the Constitution: You must be willing to support and defend the Constitution, and you affirm this when you take the Oath of Allegiance.
• Selective Service (if applicable): Most men who lived in the U.S. as permanent residents between ages 18 and 26 must have registered with Selective Service, or be able to show the failure was not willful.

These are the durable, framework-level rules. Because eligibility turns on your specific immigration history, dates of travel, and record, verify how they apply to you at uscis.gov/citizenship or with a qualified professional before you file.

The civics and English test: which version applies to you

USCIS updated the civics test in 2025. As of this writing:

• If you file Form N-400 before October 20, 2025, you take the 2008 civics test (100 possible questions, 10 asked at the interview, 6 correct needed to pass).
• If you file on or after October 20, 2025, you take the 2025 civics test (128 possible questions, 20 asked, 12 correct needed to pass).
• Applicants who are 65 or older with 20+ years as a permanent resident answer from a shorter, specially designated list of questions regardless of which test version applies.

Because test content and policy continue to evolve, always confirm the current version and official study materials at uscis.gov/citizenship rather than relying on outside study guides, which can go stale.

What to do: the N-400 process step by step

1. Confirm your eligibility date. You may file Form N-400 up to 90 days before you complete your 5-year (or 3-year) permanent residence requirement — check the exact date against your green card anniversary using USCIS's early filing guidance.
2. Gather documents. This typically includes your green card, tax records or an IRS transcript, records of trips abroad, marriage/divorce records if relying on the 3-year rule, and any court/arrest records if you have any criminal history — even if resolved or expunged. Do not omit anything; USCIS cross-checks records.
3. File Form N-400. You can file online through your USCIS account or by paper. Confirm you are using the current form edition listed on uscis.gov/n-400, since USCIS periodically updates the form and rejects outdated editions.
4. Pay the fee — but check it first. The filing fee changes periodically and USCIS has proposed a significant fee increase (with elimination of the reduced-fee and fee-waiver options) that was still in the public comment/rulemaking process as of mid-2026. Do not rely on a number you saw online or in this article — use the official USCIS Fee Calculator and the Fee Schedule the same day you file.
5. Attend biometrics (fingerprints and photo) if scheduled — reuse of prior biometrics is sometimes permitted.
6. Attend your interview. A USCIS officer reviews your application under oath, tests your English (reading, writing, speaking) unless exempt, and administers the civics test.
7. Receive a decision: approved, continued (if more evidence or a retest is needed), or denied.
8. Take the Oath of Allegiance. This is the final step that legally makes you a U.S. citizen — you are not a citizen until you take the oath, even after approval.

Deadlines to know

• Early filing window: up to 90 days before you meet the residence requirement — filing too early will result in a rejection or denial.
• If your N-400 is denied and you want to challenge it administratively, Form N-336 (Request for a Hearing) generally must be filed within 30 calendar days of receiving the denial decision (33 days if mailed to you). This deadline is strictly enforced, and a late request is normally rejected — verify current instructions on uscis.gov/n-336 before your clock runs out.
• Retest window: if you fail the English or civics test at your first interview, USCIS generally reschedules a second interview/test 60 to 90 days later — failing again typically results in denial.

A note on fraud and unauthorized "help"

Naturalization mistakes — a missed disclosure, a bad filing, an unqualified preparer's error — can lead to denial, delay, or in serious cases immigration consequences beyond the N-400 itself. Be especially careful of "notarios" or unlicensed immigration consultants who are not authorized to practice immigration law in the United States; using one is a common source of fraud and bad advice. For help, use a licensed immigration attorney or a representative accredited by the Department of Justice's Executive Office for Immigration Review (search the DOJ recognition and accreditation roster — or ask USCIS directly), and rely only on official sources: uscis.gov, justice.gov/eoir, and travel.state.gov.

This article is general information, not legal advice, and does not create an attorney-client relationship. For advice about your specific situation, consult a qualified immigration attorney or a DOJ-accredited representative.