Form N-400 is the official U.S. immigration form used to apply for American citizenship through naturalization. Its full name is the Application for Naturalization, and it's filed with U.S. Citizenship and Immigration Services (USCIS). The form is the central document in the naturalization process — submitting it is how a lawful permanent resident formally begins the process of becoming a U.S. citizen. Everything that follows — the biometrics appointment, the interview, the civics and English tests, and the oath ceremony — flows from the N-400 submission.
The N-400 is part of USCIS's broader system of immigration forms, each designated by a letter-number code. The N prefix indicates the form relates to naturalization and citizenship, as opposed to I-prefix forms (immigration benefits) or A-prefix forms (criminal history). Within the N series, Form N-400 is by far the most commonly filed — it covers the standard naturalization pathway for permanent residents who meet the physical presence, good moral character, and other statutory requirements for citizenship.
Not every permanent resident files the N-400 on the same timeline. Most permanent residents must wait five years from receiving their green card before becoming eligible to apply. The exception is permanent residents married to U.S. citizens, who become eligible after three years. Members of the U.S. military and their families may have different eligibility timelines depending on their service status. Understanding your specific eligibility window is the first step — filing before you're eligible results in a rejected application and a lost filing fee.
The form itself is substantial. As of the most recent version, Form N-400 runs more than 20 pages and covers a comprehensive range of personal history: biographical information, travel history, employment history, organizational memberships, and a detailed moral character section that asks about criminal history, tax compliance, and political affiliations. The thoroughness of the form reflects USCIS's intent to conduct a complete background review of every applicant as part of the naturalization process.
This guide explains the N-400 immigration form from start to finish: what it covers, how to obtain the current version, how to complete it accurately, what fees apply, where to submit it, and what to expect after you file. Whether you're preparing to file for the first time or helping a family member navigate the process, this guide gives you a complete picture of how the N-400 fits into the U.S. naturalization system.
The N-400 is technically an immigration form in the sense that it's filed with USCIS, the federal agency that administers immigration and nationality law. However, naturalization is distinct from immigration in the traditional sense. Immigration involves obtaining the right to enter and live in the United States — a process covered by forms like Form I-485 (for adjustment of status) or Form I-130 (for family petitions). The N-400 is filed after that process is complete: only lawful permanent residents may file it.
People who are not yet permanent residents cannot file the N-400. A visa holder, a DACA recipient, a temporary protected status beneficiary, or an undocumented person cannot use Form N-400 to apply for citizenship. These pathways don't bypass the permanent residence stage — the N-400 is the last step in a longer immigration process, not a shortcut. If you're not yet a permanent resident, your path to citizenship starts with the immigration forms that lead to a green card, not with the N-400.
The N-400 is also not a renewal, extension, or replacement for your green card. Permanent residence and citizenship are legally distinct statuses. Filing the N-400 does not change your permanent resident status until the naturalization process is complete and you take the Oath of Allegiance. During the processing period — which can last a year or more — you remain a lawful permanent resident. If your green card expires while your N-400 is pending, you should renew it — a pending N-400 doesn't automatically extend or replace your green card.
Form N-400 is always free to download from the USCIS website (uscis.gov). The filing fee is separate from the form itself and is paid when you submit your application. Be cautious of third-party websites that charge fees for downloading immigration forms — USCIS forms are public documents available at no cost. The only payment required is the filing fee paid directly to USCIS when submitting the completed application and supporting documents.
Most applicants must be permanent residents for 5 years (or 3 years if married to a U.S. citizen), meet continuous residence and physical presence requirements, demonstrate good moral character, pass the civics and English tests, and be willing to take the Oath of Allegiance.
Form N-400 collects biographical information, address and employment history, travel history, marital and family history, organizational memberships, good moral character questions (criminal history, taxes, affiliations), and an eligibility statement requiring your signature and certification.
Most applicants need their green card copy, passport photos, and government-issued ID. Additional documents may be required for specific situations: marriage certificates for spousal eligibility, military discharge papers for military applicants, or divorce decrees for applicants with prior marriages.
File online through your USCIS account at myaccount.uscis.gov ($710 fee) or by mail to the USCIS lockbox facility ($760 fee). Online filing is generally faster to process and allows you to track your application status in real time through your USCIS account.
Download the current version of Form N-400 directly from uscis.gov. USCIS updates its forms periodically, and using an outdated version will result in your application being rejected. Each form version displays the edition date in the lower-left corner of the first page. When you download N-400 from the USCIS website, you're guaranteed to have the current accepted version. Do not use forms from third-party websites, legal self-help publications, or prior filings — always download fresh from USCIS.
The form is fillable as a PDF, meaning you can type directly into the fields using Adobe Acrobat or a compatible PDF application. Complete it digitally before printing to reduce errors and improve legibility. If you must fill it out by hand, use black ink and print clearly. USCIS must be able to read every entry. If you make an error, draw a single line through the mistake, write the correction, and initial the change. Do not use correction fluid — USCIS will not accept forms with white-out or heavily altered entries.
The moral character section of N-400 is the section where applicants are most likely to make mistakes. It asks detailed questions about arrests, charges, crimes, tax compliance, organizational memberships, and political affiliations going back many years. Answer every question truthfully — USCIS cross-references your N-400 answers against FBI background check results, tax records, and other federal databases. A discrepancy between your answers and official records is treated as a potential fraud issue, which can result in denial and may affect future immigration applications.
If a question doesn't apply to you, write N/A — don't leave it blank. Blank fields signal an incomplete application. If you've ever been arrested — even for an offense that was dismissed, expunged, or for which you received a pardon — answer Yes to the relevant question and attach a certified copy of the court record. Answering No to arrest questions when an arrest exists in your record is one of the most common and consequential errors on the N-400, as it can be characterized as willful misrepresentation.
For the travel history section, list all international trips you've taken in the past five years (or three years if applying under the spouse of citizen pathway). You need the dates of departure and return, the countries visited, and the purpose of travel. If you've traveled extensively, compile this list from your passport stamps, travel records, or calendar before sitting down to complete the form. The physical presence calculation — ensuring you've been in the U.S. for the required number of days in the statutory period — depends on the accuracy of your travel record.
Before filing the N-400, confirm you meet the basic eligibility criteria for naturalization.
Permanent resident status: You must be a lawful permanent resident (green card holder) at the time of filing. You cannot file N-400 if your green card has been abandoned, revoked, or is under removal proceedings.
Continuous residence: You must have maintained continuous residence in the U.S. for 5 years (3 for spouses of U.S. citizens). A single trip outside the U.S. of more than 6 months may disrupt continuous residence and require additional documentation or re-starting the clock.
Physical presence: Within the statutory period, you must have been physically present in the U.S. for at least half the days — 913 days for the 5-year period, or 548 days for the 3-year period. Count carefully using your travel records.
Good moral character: You must demonstrate good moral character for the statutory period. Certain crimes permanently bar naturalization regardless of time elapsed. Others are bars for a defined period. An immigration lawyer should review your criminal history before you file if you have any prior arrests or charges.
The filing fee for Form N-400 depends on how you file.
Online filing: $710 total (as of the current USCIS fee schedule). Pay by credit card, debit card, or bank account withdrawal through your USCIS online account. Biometrics services are included in the fee and no separate biometrics fee is required for most applicants.
Paper filing: $760 total. Pay by personal check, money order, or cashier's check made payable to "U.S. Department of Homeland Security." Do not use cash. Include payment with your paper application package.
Fee waiver: If you receive means-tested public benefits (Medicaid, food stamps, SSI, etc.) or your household income is at or below 150% of the federal poverty guidelines, you may qualify for a fee waiver. Submit Form I-912 (Request for Fee Waiver) with your N-400 application. If approved, no fee is required.
Reduced fee: Applicants with household income between 150% and 200% of federal poverty guidelines may qualify for a reduced fee of $405. This option is available for paper filing only — submit Form I-942 (Request for Reduced Fee) with your application.
After USCIS receives your N-400, several steps follow before you become a U.S. citizen.
Receipt notice: USCIS mails Form I-797 (receipt notice) within a few weeks of receiving your application. This notice contains your receipt number, which you use to check your case status online.
Biometrics appointment: USCIS schedules a biometrics appointment at an Application Support Center (ASC) near your address. You'll provide fingerprints, a photograph, and a signature for background check processing.
Interview: After your background check clears, USCIS schedules your naturalization interview at your local field office. Bring your appointment notice, green card, passport, and any documents that relate to your application. At the interview, you take the civics test (up to 10 questions from the 100-question civics test) and demonstrate English ability.
Decision: After the interview, USCIS approves, continues, or denies your application. Approval leads to a ceremony scheduling notice; a continuation means USCIS needs more information; a denial includes appeal rights.
These are the most frequent errors on Form N-400 that cause delays, requests for evidence, or denials.
Using an outdated form version: USCIS updates forms periodically. Using a prior version means automatic rejection. Always download N-400 directly from uscis.gov immediately before filing.
Leaving fields blank: Every field must be completed. Write "N/A" for items that don't apply. Blank fields trigger a request for additional information and delay processing.
Inaccurate travel history: Incomplete or incorrect travel records affect your physical presence calculation. Compile your complete travel history before filling out the form — go back 5 years (or 3 if applicable).
Incomplete moral character section: Failure to disclose arrests — even dismissed cases, juvenile records, or expunged offenses — is treated as misrepresentation. Disclose and attach court documentation for every arrest, regardless of outcome.
Wrong fee or missing payment: Paper applications sent with incorrect payment amounts or missing payment are returned without processing. Verify the current fee schedule on uscis.gov before mailing your application.
USCIS updated its fee schedule in 2024, and the N-400 fee depends on your filing method. Online filing costs $710 and paper filing costs $760 — the difference reflects USCIS's administrative cost savings from electronic processing. Both fees include biometrics services, meaning you don't pay a separate $85 biometrics fee as was the case under the prior fee schedule. The fee is paid directly to USCIS — no payment goes to any court, attorney, or processing center outside USCIS.
Fee waivers are available for applicants who qualify. If your household income is at or below 150% of the federal poverty guidelines, or if you currently receive means-tested public benefits such as Medicaid, Supplemental Nutrition Assistance Program (SNAP), Supplemental Security Income (SSI), or Temporary Assistance for Needy Families (TANF), you may be eligible for a complete fee waiver. Submit Form I-912 (Request for Fee Waiver) simultaneously with your N-400. Approval of the fee waiver request is not guaranteed — USCIS reviews each request on its merits.
Applicants whose income falls between 150% and 200% of the federal poverty guidelines may qualify for a reduced fee of $405, available on paper applications only. This option requires submitting Form I-942 (Request for Reduced Fee). USCIS requires documentation of your income — typically a recent pay stub, tax return, or benefits letter — to verify eligibility. If you're uncertain which fee category applies to your household, USCIS's fee waiver guidance page on uscis.gov provides income thresholds and documentation requirements updated annually.
Military applicants and their qualifying family members may file N-400 without paying any filing fee under specific provisions of U.S. immigration law. If you are serving or have served honorably in the U.S. armed forces and are applying under military naturalization provisions (Section 328 or 329 of the Immigration and Nationality Act), mark the military exemption on your application and attach your service documentation. The fee exemption applies automatically if you meet the military eligibility criteria.
Confirm you meet the physical presence, continuous residence, and good moral character requirements. Gather your green card, passport, travel records, and any additional documents your situation requires. Download the current Form N-400 from uscis.gov.
Fill out the form carefully and completely. Review every section, especially travel history and moral character questions. Have a trusted advisor or attorney review your completed form if your situation is complex. Do not file if you have unanswered questions about eligibility.
File online through your USCIS account ($710) or mail your completed application to the designated USCIS lockbox facility ($760). Keep a complete copy of everything you submit. Track your application status online after submitting.
USCIS schedules a biometrics appointment first, then your naturalization interview. Attend both as scheduled. Bring your appointment notice, green card, passport, and documents listed in your interview notice. Study the civics test questions and the English requirement before your interview.
After approval, USCIS schedules your oath ceremony. Attend with all requested items including your green card (to surrender) and your ceremony notice. After taking the oath, you receive your Certificate of Naturalization — you're now a U.S. citizen.
The most important principle for completing N-400 is accuracy over speed. Take as much time as you need to gather your records, verify dates, and answer each question precisely. A rushed, inaccurate application creates problems that are far more time-consuming to fix than taking an extra week to prepare carefully. USCIS has access to extensive federal databases — your answers will be compared against records you may not even know exist, including FBI files, IRS records, and prior immigration applications.
For the biographical information sections — name history, address history, employment history — compile this information from your own records before you start filling in the form. Previous names, addresses going back 5 years, and employers going back 5 years are all required. If you've changed your name legally (through marriage, divorce, or court order), you must disclose all names you've ever used, not just your current legal name. USCIS uses name history to conduct thorough background checks and to verify identity across databases.
The organizational membership section asks about any groups, organizations, clubs, associations, or parties you've been a member of. Certain affiliations — with communist or totalitarian parties, terrorist organizations, or groups that advocate for the overthrow of the U.S. government — are bars to naturalization. For most applicants, the answer to these questions is straightforward. However, be thorough: religious organizations, labor unions, professional associations, civic groups, and even informal clubs may technically be organizations. When in doubt about whether to list something, include it — over-disclosure is safer than under-disclosure.
Sign and date Form N-400 only after you've completed and reviewed every section. Your signature certifies that everything in the application is true, complete, and correct to the best of your knowledge — signing a materially false application is a federal crime. If you have an attorney or accredited representative assist you, they must also complete Part 14 (Preparer's Statement) and sign separately. Failure to have your preparer sign their section when applicable results in the application being returned.
Reviewing the N-400 application process in detail before you complete the form helps you understand what USCIS is looking for in each section. The official USCIS N-400 instructions document (Form M-476) provides field-by-field guidance — it's available on the same USCIS page where you download the form. Read those instructions before completing any section you're uncertain about, and refer back to them if a question's wording is ambiguous.
After USCIS receives and processes your N-400 submission, you'll receive Form I-797 (receipt notice) by mail within a few weeks. This notice confirms your application was received by USCIS and gives you a receipt number — a 13-character alphanumeric code you use to check your application status on the USCIS website. Log into your USCIS online account (or use the free Case Status Online tool at uscis.gov) to monitor your application progress. Signing up for email and text notifications through your USCIS account means you'll be alerted each time your case status updates.
Your biometrics appointment typically comes several weeks to a few months after receipt, followed by the interview notification after your background check is processed. The gap between filing and interview varies significantly by USCIS field office — offices in high-volume metropolitan areas have longer wait times than offices in smaller cities. You can check the N-400 processing times page on the USCIS website for current estimates at your specific field office. Processing times are updated monthly by USCIS and represent median wait periods, not guarantees.
If your case exceeds the published processing time for your field office, you can submit a case inquiry (formerly called an e-Request) through the USCIS website. This triggers a mandatory review within 30 days. Congressional inquiries — filed through your U.S. Representative or Senator's office — are also available for cases significantly outside normal processing time and often produce more specific case information than standard inquiries. Throughout the process, keep your address current with USCIS — all appointment notices and decisions are mailed to your address on file, and a stale address causes missed notices and processing complications.
Every N-400 applicant must pass the civics test and demonstrate English reading, writing, and speaking ability at their naturalization interview. The civics test consists of up to 10 questions selected from the official 100-question USCIS civics test bank — you must answer at least 6 correctly to pass. If you fail the civics or English test at your first interview, you receive a second chance at a rescheduled interview. Failing at the second attempt results in application denial. See the N-400 naturalization application guide and our N-400 checklist for a complete breakdown of what to study and what to bring to your interview.