N-400 Form: How to Fill Out the Naturalization Application

Form N-400, Application for Naturalization, is the form a lawful permanent resident files with U.S. Citizenship and Immigration Services to become a U.S. citizen. The current edition is dated 01/20/25. It is 14 pages long, divided into 16 parts, and costs $710 to file online or $760 on paper as of October 2026. You can file it online through a free USCIS account or mail a paper copy to a USCIS lockbox, and you may send it up to 90 days before you reach your required years as a permanent resident.

This guide goes through the form part by part, lists the documents to gather, explains online versus paper filing and shows where paper applications go. Always download the form and instructions from the official page, uscis.gov/n-400. The PDF is free, and USCIS never charges for blank forms. This article is general information, not legal advice.

N-400 form: key facts

Who should file Form N-400

The form is for adults, age 18 or older, who hold a green card and want to naturalize. Part 1 asks you to pick exactly one basis for eligibility. The two that cover almost everyone are:

• General provision (box 1.A): you have been a lawful permanent resident for at least 5 years.
• Spouse of a U.S. citizen (box 1.B): you have been a permanent resident for at least 3 years, have been married to and living with the same U.S. citizen spouse for those 3 years, and your spouse has been a citizen the whole time.

Other boxes cover applicants under the Violence Against Women Act, spouses of U.S. citizens working abroad for qualifying employers, and current or former members of the armed forces. If you select more than one box or none, USCIS warns that the application may be delayed or rejected.

Do not use the N-400 if you are already a citizen through your parents. Children who became citizens automatically, or adults who acquired citizenship at birth abroad, document that status with Form N-600 or a passport application instead. The full eligibility rules are laid out in how to become a U.S. citizen.

When you can file

The instructions allow you to file up to 90 days before you complete the required period of continuous residence: 5 years under the general provision, 3 years as the spouse of a citizen. USCIS counts back 90 calendar days from your anniversary date. For a green card with a "Resident Since" date of January 20, 2022, the five-year anniversary is January 20, 2027, and the earliest filing date is October 22, 2026.

The early window applies only to the residence period. Everything else must already be true on the day you file. A spouse-based applicant, for example, must have been married to the citizen spouse for a full three years at filing. If the requirements are not met, the instructions say the application "will be rejected or denied," and the fee is not refunded after a denial.

Online or paper: which is better?

For most people who pay the full fee, online filing is cheaper and harder to get wrong. The online form will not let you skip a required field. Paper is the only route if you are asking for the $380 reduced fee or a fee waiver. Fee details, including a proposed increase that was still pending in October 2026, are in the N-400 fee guide.

If you file on paper, USCIS mails an Account Acceptance Notice with a code so you can still follow the case online.

N-400 instructions, part by part

The form has 16 parts. You complete Parts 1 through 11 (and 12 through 14 if they apply) before filing. Parts 15 and 16 are left blank until the interview.

Part 2: your name and your dates

Use your current legal name, not a nickname. List every other name you have used, including a maiden name, alternate spellings and names used on earlier immigration filings. The date you became a permanent resident is the "Resident Since" date on your green card.

Item 3 lets you request a legal name change as part of naturalization. A court grants it, so it becomes final only if you take the oath at a judicial ceremony. You do not need this box if your name already changed through marriage, divorce or a court order. Just attach that document.

Items 12.a to 12.c let you authorize USCIS to share your new status with the Social Security Administration so your record is updated after you naturalize. Saying yes can save a trip to a Social Security office later.

Parts 4, 7 and 8: addresses, jobs and travel

These three parts together show your continuous residence and physical presence. They must agree with each other and with your tax returns, so fill them in side by side.

• List addresses with no gaps in dates. You need a physical address so USCIS can schedule biometrics and the interview at the right office.
• List every employer and school, full time or part time, including periods of unemployment or self-employment.
• List every trip outside the United States, starting with the most recent. The form says not to include day trips completed within 24 hours. Use your passport stamps and airline records. Any trip longer than six months needs supporting evidence that you kept your U.S. residence.

Part 9: the yes or no questions

This is the longest part and the one where honesty matters most. The instructions state that your answers "help to determine whether you meet the standards for good moral character." Topics include whether you have ever claimed to be a U.S. citizen or voted unlawfully, whether you owe overdue taxes, any arrest or citation anywhere in the world, and your willingness to take the Oath of Allegiance.

Three points people often miss:

• "Ever" means ever. Arrests that were dismissed, sealed or expunged still have to be disclosed, with certified court records. Traffic incidents need documents only if they involved alcohol or drugs, led to an arrest or seriously injured someone.
• Selective Service. Almost all men who lived in the United States between ages 18 and 26 had to register. If you did not and are now between 26 and 31 (26 and 29 for spouse-based filers), you must explain why and include a status information letter from the Selective Service. Under 26, register before you apply.
• A "yes" is not an automatic denial, but a false "no" can be. Giving false testimony to obtain an immigration benefit is itself a bar to good moral character. If any answer in Part 9 is "yes," get legal advice before filing.

Part 11: sign it

USCIS rejects any unsigned form. A photocopy or scan of your handwritten signature is acceptable for filing. A typed name is not. Paper forms should be typed or printed legibly in black ink.

N-400 document checklist

USCIS publishes a checklist of initial evidence on the form page. It is a guide, not something you submit. Send legible copies, not originals, and include a certified English translation for any document in another language.

Everyone

• A copy of both sides of your Permanent Resident Card (green card)
• The filing fee payment, or a reduced fee request (Part 10 with income documents), or Form I-912 with evidence
• Current marriage certificate and proof that any earlier marriage ended (divorce decree, annulment or death certificate), if applicable
• Proof of a legal name change, if your name differs from your green card

If you are filing as the spouse of a U.S. citizen

• Proof your spouse has been a citizen for the last 3 years: birth certificate, Certificate of Naturalization, Certificate of Citizenship, passport biographical page or Form FS-240
• Your marriage certificate and proof that all prior marriages of both spouses ended
• Evidence of the ongoing marriage, such as joint tax transcripts for the past 3 years, a joint lease or mortgage, bank statements, insurance policies, and birth certificates of children

If any of these apply to you

• Trips of more than 6 months but less than 1 year: evidence of continuous residence, such as IRS tax transcripts, rent or mortgage statements, pay statements, bank or credit card statements with regular transactions, car registration and insurance
• Any arrest, charge or conviction: arrest reports, charging documents, certified court dispositions, sentencing records and proof you completed any sentence, probation or program
• Overdue taxes: IRS transcripts and a signed payment agreement showing you have filed and are paying
• Child support obligations: proof of payment, such as court or agency records
• Selective Service not registered: status information letter and a written explanation
• Disability exception: Form N-648 completed by a licensed medical professional
• Attorney or accredited representative: Form G-28
• Military service: Form N-426, or DD Form 214 or NGB Form 22 if separated
• Living outside the United States: two passport-style photos, 2 by 2 inches

Applicants inside the United States do not send photos. USCIS takes your picture at the biometrics appointment.

Where to mail a paper N-400

Online filers skip this step. Paper filers send the package to one of four USCIS lockboxes, assigned by state of residence. Each lockbox has one address for the U.S. Postal Service and a different one for FedEx, UPS or DHL.

Current and former service members and their spouses use a separate address: USCIS, Attn: Military N-400, P.O. Box 4446, Chicago, IL 60680-4446. The table shows examples only. Confirm your state and the courier address on the USCIS page "Direct Filing Addresses for Form N-400" before mailing, because USCIS says a package sent to the wrong address may take longer to process.

Paying the fee

USCIS no longer builds its paper process around checks. The fee schedule tells mail filers to pay by credit, debit or prepaid card using Form G-1450, or directly from a U.S. bank account using Form G-1650. A filer who qualifies for an exemption from electronic payment must include Form G-1651. Place the payment form on top of the package. An application with the wrong amount, including an overpayment, is rejected and returned.

What happens after you file

1. Receipt notice. USCIS issues Form I-797C with your receipt number. For applications filed on or after December 12, 2022, it also extends your green card for 24 months from the "Card Expires" date, so keep it with the card.
2. Biometrics notice. Most applicants are scheduled at an Application Support Center for fingerprints and a photo.
3. Possible Request for Evidence. Answer by the deadline on the notice, with everything requested in one response.
4. Interview notice. Your local field office schedules the citizenship interview, where you also take the citizenship test.
5. Decision and oath. If approved, you are scheduled for the oath ceremony.

How long all of this takes depends heavily on your field office. Current figures for all 90 offices are in our N-400 processing time guide.

If you move while the case is pending, update your address with USCIS right away through your online account. A notice sent to an old address is the most common reason people miss a biometrics or interview appointment.

Ten mistakes that get an N-400 rejected or delayed

1. Using an old edition, or mixing pages from different editions
2. Leaving the form unsigned
3. Paying the wrong amount, or paying the online fee with a paper form
4. Filing more than 90 days before the anniversary
5. Checking more than one eligibility box in Part 1
6. Gaps in the address or employment history
7. Leaving out short trips abroad, so the travel list does not match passport stamps
8. Answering "no" to an arrest question because the case was dismissed
9. Sending foreign-language documents without certified translations
10. Mailing the package to the wrong lockbox

Do you need a lawyer to file?

No. The form is designed for applicants to complete themselves, and USCIS data for fiscal year 2024 show that 17.8% of people who naturalized had an attorney or accredited representative on file, which means the large majority filed on their own. A simple case, with five clean years, no long trips, no arrests and taxes filed, rarely needs paid help.

Get advice first if you have any criminal history, trips abroad longer than six months, unfiled or unpaid taxes, a past false claim to citizenship, or doubts about how you got your green card. Nonprofit organizations recognized by the Department of Justice offer low-cost help in many cities. Avoid "notarios" and consultants who are not attorneys or accredited representatives. They are not authorized to give immigration legal advice.