Form N-400 guide: Application for Naturalization

Wang Law Firm, LLC · David Wang, Managing Attorney · Attorney-reviewed · Updated October 2026

Form N-400's official title is Application for Naturalization. It is handled by U.S. Citizenship and Immigration Services (USCIS) and is the form a U.S. lawful permanent resident (green card holder) uses to apply to become a U.S. citizen through naturalization. It is the "last step" after the green card: once the application is approved and you take the oath, you become a U.S. citizen and receive a Certificate of Naturalization.

The basic naturalization requirements (years as a green card holder, continuous residence, days physically present in the U.S., and so on) are summarized in From green card to citizen: N-400 requirements and process. This page focuses on the form itself: what goes in each part, common mistakes, what evidence to attach, what happens after filing, and recent policy changes to watch. Before filing, you can use the N-400 naturalization date and days-in-the-U.S. calculator to estimate your earliest filing date.

At a glance

Who can file, and who should not

Part 1 of Form N-400 asks you to select the basis of your eligibility for naturalization. The common ones are:

• General path (5 years): you have held a green card for 5 years, resided continuously during that time, and been physically present in the U.S. for at least 30 months (INA 316(a)).
• Spouse of a U.S. citizen (3 years): you have held a green card for 3 years, have been married to and living with the same U.S. citizen spouse throughout those 3 years, your spouse has been a U.S. citizen during all 3 years, and you have been physically present in the U.S. for at least 18 months (INA 319(a)).
• Spouse of a U.S. citizen working abroad in certain jobs: if your spouse is regularly stationed abroad by the U.S. government, certain U.S. companies or international organizations, you may apply under INA 319(b). The usual residence period does not apply, but other special requirements do.
• Military categories: people serving in the U.S. armed forces under INA 328 and 329 have separate requirements and procedures.

You should not file Form N-400 if:

• You may already have become a U.S. citizen automatically through a parent (for example, you lived in the U.S. as a green card holder before age 18, in the custody of a parent who naturalized). In that case, consider filing Form N-600 for a Certificate of Citizenship instead of Form N-400. Form N-400 asks about your parents partly to identify this situation.
• Your Certificate of Naturalization was lost or needs correcting: use Form N-565.
• Green card holder children under 18 cannot file Form N-400 themselves; those living in the U.S. with a U.S. citizen parent may acquire citizenship automatically by law.

Legal basis and eligibility requirements

The main legal bases for naturalization are sections 316 (general requirements), 319 (spouses of citizens), 312 (English and civics), 334 (filing the application), 335 (investigation and interview) and 337 (oath) of the Immigration and Nationality Act (INA), and 8 CFR parts 316, 319, 312, 334, 335 and 337. USCIS's detailed standards are in Volume 12 of the USCIS Policy Manual. The core requirements:

1. Time as a green card holder: 5 years, or 3 years for spouses of citizens. You may file within the 90 days before you reach that period (INA 334(a), 8 CFR 334.2(b)). Note: early filing only lets you "file early"; it does not shorten the period, and the application cannot be approved until the period is complete. Other requirements (such as physical presence and 3 months of local residence) must also be met as the rules require.
2. Continuous residence: a single absence of more than 6 months but less than 1 year is presumed to break continuous residence, and the presumption can be rebutted with evidence; a single absence of 1 year or more breaks continuous residence (except in special cases, such as a qualifying applicant who filed Form N-470 before being continuously abroad for 1 year and had it approved). Once continuous residence is broken by an absence of 1 year or more, you generally cannot file again until 4 years and 1 day after returning to the U.S. (2 years and 1 day for the 3-year path).
3. Physical presence: at least 30 months physically in the U.S. for the 5-year path, and at least 18 months for the 3-year path. This is a cumulative day count and is a separate requirement from continuous residence.
4. Local residence: generally, you must have lived in your state or USCIS district for 3 months before filing. Under the USCIS Policy Manual, if you file up to 90 days early, jurisdiction is based on where you lived for the 3 months before the interview; check current official rules.
5. Good moral character: you must have good moral character during the statutory period (5 or 3 years) and up until you take the oath; conduct before the statutory period may also be considered.
6. English and civics knowledge: you must be able to speak, read and write basic English and know U.S. history and government (unless you qualify for an age-and-years exception or a disability exception).
7. Attachment to the principles of the Constitution and willingness to take the oath of allegiance.

Tips for each part of the form

Form N-400 is one of USCIS's longer forms. USCIS releases new editions from time to time, and the numbering and order of the parts may change between editions. The notes below are organized by topic; when filling out the form, follow the current edition you download and its instructions.

1. Eligibility (Information About Your Eligibility)

• Check only the one primary basis for eligibility. If you file under the 3-year spouse-of-a-citizen path, the marriage section later in the form must fully support it: the date your spouse became a citizen, your marriage date, and the fact that you have been living together.
• If your spouse has been a citizen for less than 3 years, or you have been married for less than 3 years, you cannot file under the 3-year path, even if you have held your green card for 3 years.

2. Information About You

• Name: give your current legal name and list every other name you have used (including a maiden name, different romanized spellings, and English names that have appeared on your passports). For Chinese names, the order and pinyin spelling should match your green card and passport; be ready to explain any differences.
• Name change: the form asks whether you want to change your name when you naturalize. In some areas, a name change at naturalization must be done at a court-administered oath ceremony, which may affect oath scheduling; whether it is possible depends on your local USCIS office's practice.
• Green card information: your A-Number and the date you became a permanent resident (use the "Resident Since" date on your green card, not the date the card was produced).
• Disability accommodations: if you need an accommodation at the interview (such as a sign language interpreter or wheelchair access), note it in the relevant section. This is different from requesting a test exception (Form N-648).
• In recent years USCIS has proposed collecting social media account information on several forms, including Form N-400. If the edition you use includes such questions, answer them truthfully and completely; whether they are required depends on the current edition.

3. Age-based exceptions to the English and civics test

• If, at the time of filing, you are age 50 or older and have held a green card for 20 years, or age 55 or older and have held a green card for 15 years, you are exempt from the English test and may take the civics test in your native language (bringing your own interpreter); if you are 65 or older and have held a green card for 20 years, you may also study a special simplified set of questions (INA 312(b)).
• The years are counted from the date you became a permanent resident, and your age is determined as of the date you file Form N-400.

4. Information About Your Residence

• List every address for the period the form requires (see the current edition's instructions), with dates that connect end to end and no gaps.
• Include addresses where you lived abroad. Your address history should broadly line up with your travel history, tax filing addresses and work locations.

5. Information about your parents

This is used to determine whether you have already acquired U.S. citizenship through a parent. If one or both of your parents are U.S. citizens, especially if they naturalized before you turned 18, assess whether Form N-600 applies before filing.

6. Marital status and marital history

• Report your current marriage, the number of prior marriages, and your spouse's prior marriages truthfully. If your spouse is a U.S. citizen, give how and when he or she became a citizen.
• On the 3-year path, "living in marital union" is a substantive requirement. Spouses who live apart for long periods, for example for work, may have trouble meeting it.

7. Children

List all of your children, including adult children, stepchildren, adopted children, children living abroad, deceased children, and children born outside of marriage. Leaving out children is a common problem and can lead to questions about your truthfulness and your child support obligations.

8. Employment and schools

List your work and school history for the period the form requires, including self-employment, periods of unemployment and work abroad. For periods without work you can write "unemployed" and explain how you supported yourself. Employment information should match your tax records.

9. Time Outside the United States

• For the period the form requires, list every trip outside the U.S. longer than 24 hours, including short trips to Canada and Mexico.
• Make the dates as accurate as possible by checking passport entry and exit stamps and flight records; you can also look up your CBP I-94 travel history for reference. Officers check what you report against government records.
• For any single trip of 6 months to 1 year, prepare evidence that your continuous residence was not broken (see "Evidence and supporting documents" below).
• If your travel history is long or complicated, first use the calculator to check whether your total days in the U.S. reach 30 or 18 months.

10. Additional Information: moral character and eligibility questions

This is the most important part of Form N-400 and the one most likely to cause problems. It contains dozens of "yes / no" questions covering:

• Whether you have ever claimed to be a U.S. citizen, or registered or voted in any election in the U.S.;
• Whether you owe taxes, or have ever filed taxes as a "nonresident" (which may be treated as abandoning permanent resident status);
• Whether you have ever been arrested, detained, charged or convicted, or committed an offense for which you were not arrested;
• Whether you have ever given false information or documents to a government official to obtain an immigration benefit;
• Whether you have ever been removed or been in removal proceedings;
• For men who lived in the U.S. between ages 18 and 26, whether you registered with the Selective Service System as required;
• Whether you have met your child support obligations;
• Your connections to certain organizations, whether you have taken part in certain unlawful activities, and so on.

Tips:

• Disclose rather than conceal. Even if a case was dismissed, or the record was sealed or expunged, you generally still have to disclose it and provide the court documents. Concealment can itself show a lack of good moral character.
• For any question you answer "yes," explain what happened on an additional sheet and attach supporting evidence.
• When reviewing Form N-400, the officer will also re-examine whether you lawfully obtained your green card in the first place. If you have any doubts, have an attorney assess your case before filing.

11. Fee reduction and signature

• Under current rules, the form includes a section to request a reduced fee for applicants whose household income falls within a specified range; if you qualify, you may also request a fee waiver separately with Form I-912. Note: on June 23, 2026, DHS published a proposed rule that would raise naturalization fees and eliminate the reduced fee option for Form N-400 and fee waivers for Forms N-400 and N-336. As of this update it is still a proposed rule; whether and when it takes effect depends on the final official publication.
• You must sign the application yourself; unsigned applications are rejected. If someone helped you fill out or translate the form, the preparer and the interpreter must also sign the relevant sections.

Evidence and supporting documents

• A copy of the front and back of your green card (if it was lost, provide substitute documents as the form instructions describe);
• 3-year path: proof of your spouse's citizenship (U.S. passport, birth certificate, Certificate of Naturalization, etc.), your marriage certificate, divorce or death certificates ending both spouses' prior marriages, and evidence of living together (such as joint tax returns, a shared lease or property, and joint accounts);
• If you have any arrests, charges or convictions: certified court dispositions, police records, and proof that you completed your sentence;
• For any single trip over 6 months: evidence that you kept working for or kept your job with a U.S. employer, kept your home, continued to file taxes as a resident, had family remaining in the U.S., and so on;
• If you owe taxes: your payment agreement with the Internal Revenue Service (IRS) and payment records; it is generally a good idea to have recent tax returns or IRS tax transcripts ready;
• If you have child support obligations: the support order and payment records;
• Male applicants who did not register with the Selective Service as required: a status information letter from the Selective Service System and an explanation;
• If you are requesting a disability exception: Form N-648, which generally must be filed together with Form N-400;
• Documents not in English need a complete English translation and a translator's certification; see Translation requirements for immigration applications. If you use documents such as a Chinese marriage certificate or divorce agreement, make sure the translation matches the original.

USCIS may ask to see originals at the interview, so bring your original documents with you.

How to file and fees

You can file Form N-400 online or mail a paper form to the officially designated filing address (lockbox); military categories have dedicated filing addresses. Filing online lets you upload evidence directly, pay online and track your case.

This page does not list specific amounts. For the current filing fee, whether online and paper filing fees differ, and the requirements for a reduced fee or fee waiver, see the USCIS fee schedule G-1055 and the official N-400 page, or read How to check U.S. immigration fees and processing times. In 2026 DHS proposed changes to naturalization fees and fee relief, so verify the latest rules before filing.

What happens after you file

1. Receipt notice (I-797C): the Received Date on it matters: it determines which version of the civics test applies to you, and the notice also serves as supporting proof of status while your naturalization is pending.
2. Biometrics: go to the Application Support Center as scheduled for fingerprints and photos, which are used for background checks; USCIS may also reuse biometrics it already has.
3. Request for evidence (RFE): USCIS may ask for court records, tax records, proof of trips abroad and so on; see What to do when you receive an RFE.
4. Interview and test: the officer will go through your N-400 answers one by one and give the English test (speaking, listening, reading and writing) and the civics test. Form N-400 applications filed on or after October 20, 2025 use the 2025 civics test: you are asked up to 20 questions orally from a bank of 128 questions and pass by answering 12 correctly; 65/20 applicants are asked 10 of a special set of 20 questions and pass by answering 6 correctly. You can prepare with the civics test practice tool. If you fail any part of the test, a retest is usually scheduled within 60 to 90 days.
5. Interview result: the officer usually issues Form N-652 with the result at the interview: approved, continued (for example, for more documents or a retest), or denied.
6. Oath: after approval you receive an oath ceremony notice (N-445). On the day of the oath you answer a pre-oath questionnaire, mainly confirming whether anything affecting your moral character has happened since the interview (for example, an arrest, travel abroad, marriage or divorce), and you turn in your green card. You officially become a U.S. citizen and receive your Certificate of Naturalization only after taking the oath. In some areas the oath can be taken on the day of the interview.

For processing times, check the official USCIS processing times; for how to check your case, see How to check your USCIS case status. After the oath, you can apply for a U.S. passport and update your Social Security record; your children under 18 who hold green cards and live with you in the U.S. may automatically acquire citizenship under INA 320, which they can document through Form N-600 or a passport application.

Recent changes to watch

• 2025 civics test: applies to Form N-400 applications filed on or after October 20, 2025, with a different question bank and passing standard from the 2008 test. Applications filed earlier still take the 2008 test.
• Good moral character review: in August 2025 USCIS issued a policy memo calling for a holistic assessment of moral character: officers consider applicants' positive conduct and contributions in their communities, and also look at conduct that, while not a statutory bar, is inconsistent with the average behavior expected in the community.
• Neighborhood investigations: in August 2025 USCIS issued a memo reinstating neighborhood investigations of naturalization applicants, which may involve verifying residence, moral character and similar matters; implementation depends on USCIS's arrangements.
• Denaturalization referrals: in September 2026 USCIS updated Volume 12, Part L of the Policy Manual, changing how potential denaturalization cases are identified, prioritized and referred; the legal grounds for denaturalization themselves did not change, and denaturalization still requires a court judgment. This is another reminder that every answer on Form N-400 must be true and complete.
• Fees: a proposed rule to raise naturalization fees and eliminate the reduced fee and fee waivers was published in June 2026 (see above) and is awaiting a final rule.

These policies have changed often in recent years; verify the latest rules before filing.

Common reasons for denial, and options after a denial

• Not enough days of physical presence, or a long absence that broke continuous residence and was not rebutted;
• A record during the statutory period that affects moral character, or concealing facts such as arrests or unpaid taxes on the form or at the interview;
• Failing the test twice;
• Not meeting the marriage or marital union requirements on the 3-year path;
• Problems with how you obtained your green card (for example, you were not eligible or there was fraud), which may lead not only to a denial but also to removal proceedings;
• Not submitting requested documents, or missing the interview without good reason.

Options after a denial:

• Request a hearing: within 30 days of receiving the denial (33 days if it was served by mail), file Form N-336 to have another officer review the case; if the denial is upheld after the N-336 hearing, you may file suit in federal district court.
• Refile once the problem is resolved: for example, if you lacked enough days, you can file a new Form N-400 once you meet the requirement.
• If the denial involves the lawfulness of how you obtained your green card or criminal issues, consult an attorney promptly.

Form N-400 compared with similar forms

Frequently asked questions

Official sources

• USCIS: Form N-400, Application for Naturalization
• USCIS Policy Manual, Volume 12: Citizenship and Naturalization
• USCIS: 2025 Civics Test
• USCIS fee schedule G-1055
• Federal Register: Naturalization Application Fee Adjustments (June 2026 proposed rule)
• USCIS processing times

Related reading

• From green card to citizen: N-400 requirements and process
• N-400 naturalization date and days-in-the-U.S. calculator
• Civics test practice (2025 version)
• Form N-648 medical certification for disability exceptions
• Traveling abroad as a green card holder

This article is general information and is not legal advice. Laws and policies can change; rely on the latest official information and on an attorney's advice for your specific situation.