Eligibility & Requirements

General requirements

• Be at least 18 years old at the time you file Form N-400.
• Be a lawful permanent resident (green card holder) for the required period — 5 years for most applicants, or 3 years if married to and living with a U.S. citizen.
• Show continuous residence in the United States for that period.
• Meet the physical-presence requirement (be in the U.S. for at least half the period).
• Have lived for at least 3 months in the state or USCIS district where you file.
• Demonstrate good moral character.
• Be able to read, write, and speak basic English, and pass the U.S. civics test.
• Show attachment to the principles of the U.S. Constitution and take the Oath of Allegiance.

The 5-year vs. 3-year rule

The general rule requires 5 years as a permanent resident. The 3-year rule applies if you have been married to and living with the same U.S. citizen for the last 3 years, and that spouse has been a citizen for all 3 of those years. Under either path, you may file your N-400 up to 90 days early — use our N-400 Eligibility Date Calculator to find your exact earliest filing date. (See USCIS Policy Manual, Ch. 6.)

Continuous residence & physical presence

Continuous residence means keeping the U.S. as your home for the whole statutory period. A trip abroad of more than 6 months (181+ days) is presumed to break it, and a trip of a year or more (365+ days) automatically breaks it. Physical presence is the total time you were actually in the country — at least 30 months out of 5 years (or 18 months out of 3 years). Details are in USCIS Policy Manual, Ch. 3 and the continuous-residence overview.

Good moral character

USCIS reviews your conduct during the statutory period (and can look further back). Certain offenses — such as some crimes, failing to pay child support, or lying to immigration officials — can be permanent or temporary bars. If you have any arrests or legal issues, talk to an immigration attorney before filing.

English & civics — and the exceptions

You must generally read, write, and speak basic English and pass the civics test. Some applicants qualify for accommodations:

• 50/20 and 55/15 exceptions: if you are 50+ with 20 years as an LPR, or 55+ with 15 years, you may take the civics test in your language and are exempt from the English requirement.
• 65/20 special consideration: if you are 65+ with 20 years as an LPR, you study a smaller set of civics questions (the 20 marked with a star).
• Medical disability (Form N-648): a qualifying physical or developmental disability or mental impairment may exempt you from the English and/or civics requirements.

See the official USCIS study materials and exceptions for current details.