U.S. Citizenship Application Guide: 2027 Edition
Form N-400, the interview, and the 2025 civics test — in plain English.
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U.S. Citizenship Test Study Guide: 2027 Edition
Flashcards give you the answers. This tells you which test you are actually taking, what the interview is like, and why each answer is right.
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When can I apply for citizenship?
Most people can file Form N-400 once they have held a green card for 5 years, or 3 years if they have been married to and living with a U.S. citizen for those 3 years (how the 3-year rule works). USCIS also allows filing up to 90 days before that anniversary — but filing even one day too early gets the application rejected, so the exact date matters.
Our Early Filing Calculator works out that date from your own green card, in your browser.
Have I spent too much time outside the U.S.?
You need to have been in the U.S. for at least half of the 5 years before you file (913 days), or half of 3 years on the marriage path (548 days). Separately, one trip of more than 180 days can raise a question about continuous residence, and a trip of a year or more resets the clock.
Our Travel Days Calculator adds up your trips and flags any long ones. How long trips are treated.
Which civics test do I take?
USCIS changed the citizenship civics test in October 2025. Which version you should study depends on the date you filed Form N-400, not the date of your interview: file before October 20, 2025 and you take the older 100-question test; file on or after that date and you take the new 128-question test.
Our Civics Test Checker tells you which one applies to you.
This is general information, not legal advice. Speak with an immigration attorney about your own situation.