- The N-400 form is the primary application for naturalization for eligible green card holders seeking U.S. citizenship.
- Most applicants require five years of residence, while spouses of U.S. citizens may apply after three years.
- Applicants must demonstrate English literacy and civics knowledge unless they qualify for age-based or medical waivers.
Form N-400 is the main filing for a green card holder who wants U.S. citizenship through naturalization. USCIS requires the current edition from its website, and every page must match the latest version or the case can be rejected. The official USCIS Form N-400 page is the safest starting point, and the same rule applies to related forms such as Form I-751, Form N-648, Form I-912, and Form N-336.
The Application for Naturalization is not a simple identity form. It asks USCIS to review residence, travel, marriage history, work history, tax compliance, criminal history, and English and civics skills. According to analysis by VisaVerge.com, many delays start when applicants treat it like a basic filing instead of a full legal review.
Filing rules that decide eligibility
Most applicants must be at least 18 and hold a valid green card throughout the process. Conditional residents first need to remove conditions with Form I-751 before they file for citizenship. Most permanent residents can apply after five years of continuous residence. Spouses of U.S. citizens who live in marital union can apply after three years.
USCIS allows filing up to 90 days early before the residency period is fully met. That helps applicants prepare without losing time. Continuous residence means keeping the United States as the main home. Trips under six months usually do not break that pattern, but longer absences require proof of ties such as tax returns, property records, or family records.
Physical presence is a separate rule. Applicants must be in the United States for at least half of the required period: 30 months under the five-year rule and 18 months under the three-year rule. USCIS also reviews good moral character during the full eligibility period. Serious crimes, tax evasion, and other unlawful acts can block approval.
English, civics, and medical waivers
Most applicants must show basic English skills in speaking, reading, and writing. They also must pass a civics test on U.S. history and government, with 6 of 10 answers correct. Older applicants get some relief. People over 50 with 20 years as permanent residents can take civics in their native language. People over 65 with 20 years get a shorter civics list. Medical disabilities can qualify for an English or civics waiver through Form N-648.
Military members follow a faster path. Active-duty service members under INA sections 328 and 329 may apply without the usual wait times. They often receive fee relief and priority handling.
What USCIS asks for in the form
Form N-400 goes far beyond a few personal details. Part 2 asks for five years of address history, with exact move-in and move-out dates. P.O. boxes do not count. Part 4 covers marital status, past marriages, and the spouse’s immigration status. That section matters most for three-year applicants, who need proof that the marriage is real.
Part 6 asks for five years of work history, including gaps in employment, plus education. Parts 7 through 12 probe sensitive issues: arrests, even if dismissed or expunged; affiliations since age 16; taxes; public benefits; and any oath to a foreign government. Every answer must be complete. Blank spots and missing details invite fraud review.
USCIS expects honesty under penalty of perjury. False statements can bring denial, a long reapplication bar, or removal proceedings. The agency checks FBI databases, IRS records, and other government systems.
Documents that should go with the filing
Applicants should send photocopies, not originals, unless USCIS asks for them. A strong package usually includes:
- Front and back copy of the green card
- Two passport-style photos with the name and A-number written on the back
- Marriage certificate and proof of the spouse’s citizenship for three-year cases
- Certified court records for every arrest or charge, even minor or dismissed cases
- Selective Service proof for men who were 18 to 26
- Travel tie documents such as tax returns, leases, deeds, or affidavits
USCIS wants the package organized in the same order as the form. Missing records often lead to a Request for Evidence, which pushes the case back by months.
Fees and payment rules in 2026
The standard N-400 fee is $725 for applicants ages 18 to 74. That total includes the filing fee and biometrics fee. Applicants age 75 and older pay $640 because biometrics are waived. Military applicants often qualify for full waivers. Low-income applicants can use Form I-912 for a fee waiver if household income is below 150% of the poverty guidelines. Reduced fees are available at 150% to 200%.
Paper filers must pay by check or money order made out to U.S. Department of Homeland Security, unless they use the card option where allowed. Missing payment or using the wrong amount leads to rejection.
Online filing, paper filing, and the first notices
USCIS lets many applicants file online through a personal account. Online filing gives instant confirmation, status tracking, and digital upload tools. Paper applicants mail the form to the correct lockbox address listed in the instructions. The current edition number matters. An older version is rejected automatically.
A receipt notice, usually Form I-797C, typically arrives in 3 to 4 weeks. That notice includes the receipt number used for tracking. A biometrics appointment usually follows. The appointment at an Application Support Center often takes about 30 minutes.
The usual path from receipt to oath
Median processing reached 5.5 months in FY2025, when USCIS completed 878,500 naturalizations, up from 818,500 in FY2024. The journey usually moves in five stages. First comes receipt and biometrics. Then USCIS sends an interview notice, often 3 to 6 months later. The interview lasts about 1 to 2 hours.
At the interview, the officer reviews the N-400, checks identity documents, and tests English and civics. Applicants should bring originals and any updated records, including a new address or new marriage evidence. After the interview, USCIS may approve the case the same day, continue it for a retest within 90 days, or deny it. A denied case can be appealed with Form N-336, which now costs $700.
After approval, the oath ceremony usually follows in weeks. That final step turns the green card holder into a U.S. citizen.
Errors that slow cases down
USCIS uses fingerprint checks, name checks, and other interagency systems to spot fraud. Common mistakes include leaving blanks instead of writing “N/A,” failing to list every address or job, hiding arrests, using the wrong form edition, and sending weak marriage evidence. For applicants with criminal records, early legal review matters because some bars are permanent and others are waivable.
Families often use the three-year path, but divorce before the oath usually resets the case to the five-year rule. Workers who travel should keep detailed proof of U.S. ties. Seniors and military applicants gain the clearest cost and time advantages. With careful filing, the Application for Naturalization becomes a direct path from permanent residence to full citizenship rights.
