How to Become a United States Citizen: N-400, Tests, and Oath

To become a United States citizen through naturalization, you generally need to live in the country as a lawful permanent resident for five years (three if you’re married to a U.S. citizen), show good moral character during that time, pass English and civics tests, and take the Oath of Allegiance. Median processing on the application itself runs about 6.4 months, though the residency clock before you can even file is the longer wait.¹ Once you finish, you can vote in federal elections, apply for a U.S. passport, and serve on a federal jury.²

Who Qualifies to Naturalize

The baseline rule under federal law is five continuous years as a lawful permanent resident before filing.³ On top of that, you must have been physically present in the country for at least half of those five years, which comes out to 30 months. Continuous residence and physical presence are separate tests: one asks whether you kept your home in the U.S., the other simply counts days on U.S. soil.

If your spouse is a U.S. citizen and you’ve been living in marital union for at least three years, the residency requirement drops to three years and the physical presence requirement to 18 months.⁴ Your spouse must have held citizenship for that entire three years, and you must still be married when USCIS interviews you.

You can file the application up to 90 days before you actually hit the residency mark, which puts you in the processing queue sooner. USCIS still won’t approve you until you’ve reached the full five or three years.⁵

Keeping Your Residency Intact

Long trips abroad are the quiet way people disqualify themselves. Leave the U.S. for more than six months but less than a year during your statutory period, and USCIS will presume you broke continuous residence. You can rebut that presumption with evidence that you kept your job, kept your home, and your family stayed here, but the burden is on you.⁶

An absence of a year or more automatically breaks continuous residence. Unless you got prior approval by filing Form N-470 before you left, USCIS must deny the application and your residency clock restarts.⁶ Even after filing, keep tracking your travel. The interviewing officer will ask about every trip taken between filing and the interview.

Good Moral Character and Criminal History

USCIS looks at your conduct across the entire statutory period and up through the oath ceremony. The standard is called good moral character, and it covers criminal history, tax compliance, and obligations like child support.³ Conduct from before that period can still be considered if it bears on who you are now.

Some offenses are automatic bars. A conviction for an aggravated felony at any point in your life permanently disqualifies you, as does involvement in Nazi persecution, genocide, torture, or extrajudicial killings. Inside the statutory period, spending 180 or more days confined in a penal institution, deriving your main income from illegal gambling, two or more gambling convictions, or giving false testimony to obtain an immigration benefit all bar approval. Convictions involving moral turpitude and controlled substance offenses (with a narrow exception for a single simple-possession offense of 30 grams or less of marijuana) are also disqualifying.⁷

If you have any criminal record, including arrests that never led to convictions, talk to an immigration attorney before filing. The interview is under oath, and hiding a record is fraud that permanently bars citizenship on its own.

Selective Service Registration

Men living in the United States, including lawful permanent residents, must register with the Selective Service System between ages 18 and 25.⁸ A knowing and willful failure to register that falls inside your statutory period is a good moral character problem. If you’re under 26, register now. If you’re 26 to 31 and never registered, request a Status Information Letter from Selective Service and submit it with a written explanation showing the failure wasn’t deliberate. Past 31, the failure typically sits outside your statutory period, but an explanation is still worth including.

The English and Civics Tests

At the interview, an officer tests your English by asking you to read one sentence correctly out of three and write one sentence correctly out of three. Your speaking ability is judged from how you answer the officer’s questions throughout the interview itself. The civics portion draws from a published list of 100 questions on U.S. history and government; the officer asks up to 10, and you need 6 correct to pass. USCIS posts free study materials, flash cards, and practice tests on its website.

Age and Disability Exceptions

Long-term residents get accommodations. Under the 50/20 rule (age 50 with 20 years as a permanent resident) and the 55/15 rule, you’re exempt from the English test and can use an interpreter for civics. Under the 65/20 rule, you’re exempt from English and take a simplified civics test with an interpreter allowed.⁹

If a physical or developmental disability or mental impairment lasting at least 12 months keeps you from learning English or civics, submit Form N-648 with your N-400. It has to be signed by a licensed medical doctor, doctor of osteopathy, or clinical psychologist explaining how each condition blocks you from meeting the requirement.¹⁰ The exception doesn’t apply when the disability comes solely from illegal drug use. Even with a full waiver, you still have to show you understand the Oath of Allegiance, but you can show that in any language and by any method, including a nod.

If You Fail a Test

Failing English or civics at the interview isn’t the end. USCIS must give you a second try within 60 to 90 days, and you’re retested only on the portion you failed.¹¹ Fail again and USCIS denies the application; you’d need to refile and repay the fee.

Filing Form N-400

The application is Form N-400, available for online or paper filing.¹² It asks for detailed residential, employment, travel, and family history. Every international trip during the statutory period has to be listed with dates. If you traveled a lot, work backward from your passport stamps before you start typing.

Gather these documents:

A copy of both sides of your permanent resident card.
Two recent passport-style photographs meeting USCIS specifications.
If applying through marriage: your marriage certificate, proof of your spouse’s citizenship, evidence you live together, and divorce decrees or death certificates for any prior spouses on either side.
IRS tax transcripts covering your statutory period.
Court orders or other official records if your current legal name differs from what appears on your immigration documents.

Answer every question truthfully. Omissions or misstatements, even on minor matters, can be treated as fraud and trigger a permanent bar. Check every signature before you submit.

Fees and Fee Waivers

USCIS charges a filing fee for the N-400 that includes biometrics. Fees were inflation-adjusted effective January 1, 2026, and the amount depends on whether you file online or on paper, so pull the current fee schedule (Form G-1055) before you file.¹²

Households earning under 400 percent of the federal poverty guidelines qualify for a reduced fee of $380. Households under 150 percent, or those receiving means-tested benefits like Medicaid or SNAP, can request a full waiver using Form I-912.¹³ Beyond the government fee, plan for certified translations of foreign-language documents and passport photos. Attorney help is optional; many applicants file on their own.

After You File: Biometrics, Interview, and the Oath

USCIS mails Form I-797C, a receipt notice with a case number you can use to track the file online.¹⁴ Next comes a biometrics appointment for fingerprints, photograph, and digital signature, which feed into a federal background check.

When the background check clears, you’re scheduled for an in-person interview. The officer places you under oath, walks through the N-400, tests your English and civics, and either approves you, continues the case for more evidence, or denies it. Bring originals of every supporting document.

The final step is the Oath of Allegiance ceremony, usually at a federal courthouse or USCIS office. You swear allegiance to the United States, renounce loyalty to any foreign government, and pledge to support and defend the Constitution. You surrender your green card and walk out with a Certificate of Naturalization, your primary proof of citizenship. From that moment you can register to vote, apply for a U.S. passport, and take federal jobs that require citizenship. You’re also eligible for federal jury duty.¹⁵ Update your Social Security record so employment verification down the line doesn’t hit friction.

If Your Application Is Denied

You have a right to a hearing before a different officer. File Form N-336 within 30 calendar days of receiving the denial, or 33 if it was mailed.¹⁶ Miss the deadline and USCIS generally rejects the request and keeps the fee. At the hearing you can bring new evidence. If the hearing officer also denies, you can seek judicial review in federal district court. When the denial was just a failed test rather than an eligibility problem, refiling a new N-400 is usually simpler than appealing.

Faster Paths: Military Service and Children

Serving honorably in the U.S. Armed Forces for at least one year lets you naturalize without meeting the standard continuous residence or physical presence requirements, provided you file while still serving or within six months of honorable discharge. There’s no filing fee for the application or the certificate.¹⁷ During designated periods of hostilities, continuous residence and physical presence drop out entirely and the good moral character window shrinks to one year.¹⁸ Military applications also process faster, at a median of about 3.2 months.¹

Children born abroad don’t go through this process at all if certain conditions apply. A child can acquire citizenship at birth if a U.S. citizen parent meets the physical presence requirements in the statute.¹⁹ Under the Child Citizenship Act of 2000, a child born abroad automatically becomes a citizen once all four of these are true: at least one parent is a U.S. citizen by birth or naturalization, the child is under 18, the child is a lawful permanent resident, and the child lives in the citizen parent’s legal and physical custody in the United States.²⁰ No interview, no test. Parents can document that automatic citizenship with Form N-600, which produces a Certificate of Citizenship useful later for passports and proof of status.²¹

1
U.S. Citizenship and Immigration Services. Historic Processing Times
2
U.S. Citizenship and Immigration Services. Citizenship Rights and Responsibilities
3
Office of the Law Revision Counsel. 8 USC 1427 – Requirements of Naturalization
4
Office of the Law Revision Counsel. 8 USC 1430 – Married Persons and Employees of Certain Nonprofit Organizations
5
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part D, Chapter 6
6
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part D, Chapter 3 – Continuous Residence
7
Office of the Law Revision Counsel. 8 USC 1101 – Definitions
8
Selective Service System. Who Needs to Register
9
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part E, Chapter 2
10
U.S. Citizenship and Immigration Services. Form N-648, Medical Certification for Disability Exceptions
11
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part B, Chapter 4
12
U.S. Citizenship and Immigration Services. N-400, Application for Naturalization
13
U.S. Citizenship and Immigration Services. Poverty Guidelines
14
U.S. Citizenship and Immigration Services. Form I-797C, Notice of Action
15
United States Courts. Juror Qualifications, Exemptions and Excuses
16
U.S. Citizenship and Immigration Services. N-336, Request for a Hearing on a Decision in Naturalization Proceedings
17
Office of the Law Revision Counsel. 8 USC 1439 – Naturalization Through Service in the Armed Forces
18
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part I, Chapter 3
19
U.S. Citizenship and Immigration Services. USCIS Policy Manual Volume 12, Part H, Chapter 3
20
Office of the Law Revision Counsel. 8 USC 1431 – Children Born Outside the United States
21
U.S. Citizenship and Immigration Services. N-600, Application for Certificate of Citizenship