Form N-400: what it is and what it asks for

Form N-400, Application for Naturalization, is the application a lawful permanent resident files to become a U.S. citizen. It opens the whole process: until USCIS receives it, there is no biometrics appointment, no interview and no test.

This guide explains what the form asks and how the process works. It does not tell you how to answer in your case: that depends on your personal history, and only an immigration attorney or an accredited representative can advise you on it.

Before the form: who can apply

USCIS publishes the eligibility requirements on its N-400 page. Broadly, they cover how long you have been a permanent resident, how much time you have physically spent in the country, your good moral character, and your knowledge of English and civics.

If you are unsure whether you qualify, do not settle it on your own or on what a friend tells you. A mistake here can cost you the whole application and, in some cases, much more.

What the form asks for

The N-400 is divided into parts. Without getting into how to answer, here is what each block covers:

• Who you are. Legal name, other names you have used, A-Number, date of birth, country of origin.
• Where you live. Your current address and every address for the last five years.
• Your family situation. Marital status, previous marriages, children.
• Your work and schooling over recent years.
• Your trips outside the United States, with departure and return dates.
• Your background. Arrests, charges, detentions, taxes, military service, affiliations.
• The disposition questions, which cover your commitment to the Constitution and the oath.

The two sections where people most often go wrong are trips and background. If you had long absences from the country, any arrest (even one that was dismissed or expunged), or unpaid taxes, talk to an attorney before filing anything.

What it costs

According to the official N-400 page, verified on September 24, 2026:

• $760 if you file on paper.
• $710 if you file online.
• $380 if you qualify for the reduced fee and send the documentation that supports it.
• No fee if you qualify for a fee waiver and file Form I-912 or a written request.

One practical detail: if you request a reduced fee or a fee waiver, you cannot file online. You have to file on paper.

Fees change. Before paying, check them at uscis.gov/n-400.

How to file

There are two routes: online, by creating a USCIS account, or by mail on paper. The online account also lets you pay, check your case status, get notices and respond if USCIS asks for more evidence.

If you file on paper, USCIS later mails you a notice so you can create the account and follow the case. Your application is processed even without an account, but you lose the easy tracking.

What happens next

1. Receipt. USCIS confirms it received the application.
2. Biometrics. You are scheduled at an application support center for fingerprints and a photograph. That photo may be the one on your Certificate of Naturalization, so it is worth dressing for it.
3. Interview. An officer goes through your application with you and, unless you qualify for an exemption, gives you the English and civics tests.
4. Decision. USCIS approves, continues or denies the case.
5. Oath. If you are approved, you take the Oath of Allegiance at a ceremony. That is the moment you become a citizen.

The test that comes next

Two things are tested at the interview: English and civics.

English has three parts. Speaking, which the officer assesses while you talk through your application. Reading, where you must read aloud one of three sentences. And writing, where you must correctly write one of three sentences.

For civics, which test you take depends on when you filed the N-400:

• Filed before October 20, 2025: the 2008 test. Up to 10 questions from a list of 100, and you pass with 6.
• Filed on or after October 20, 2025: the 2025 test. 20 questions from a list of 128, and you pass with 12.

That is what this site is for: the official questions from both versions, with Spanish support and mock interviews in the real format.

When you need a lawyer

This guide is general information. Get professional help if your case involves:

• Long trips or moves outside the United States.
• Any arrest, charge or conviction, however minor it seems.
• Taxes not filed or not paid.
• Issues with the draft or with Selective Service registration.
• Questions about how you obtained residency or about previous marriages.

You can find organizations recognized by the Department of Justice, which offer free or low-cost help, in the immigration legal services directory.