Guides

N-400 guides

The rules USCIS uses to decide when you can apply for citizenship, explained with examples. Informational only, not legal advice.

• When can I apply for citizenship? N-400 eligibility explainedWork out the earliest date you can file Form N-400: the 5-year and 3-year tracks, the 90-day early filing window, physical presence and continuous residence.
• The N-400 90-day early filing rule: how to count itHow the N-400 90-day early filing rule works, how to count the days correctly, why 3 months is not 90 days, and why filing one day early leads to denial.
• Continuous residence for naturalization: trips over 6 monthsHow trips abroad affect continuous residence for the N-400: under 6 months, 6 months to 1 year, 1 year or more, Form N-470, and how to plan a safe return date.
• The physical presence requirement for citizenshipHow the N-400 physical presence rule works: 30 of 60 months (18 of 36 for marriage), how to count days outside the U.S., a worked example and records to keep.
• 2025 civics test vs 2008: which one do you take?Your N-400 filing date decides your civics test. Compare the 2025 and 2008 tests: question bank, questions asked, passing score, stop rule and how to study.
• N-400 interview documents checklistWhat to bring to your N-400 citizenship interview: identity and travel documents, tax records, marriage track proof, special situations and a day-before list.