How naturalization eligibility works
Naturalization is the process by which a lawful permanent resident becomes a US citizen by filing Form N-400. Eligibility rests on a handful of pillars: how long you have held a green card, how much time you have physically spent in the country, whether you have maintained continuous residence, and a set of character, language and civics requirements. This checker walks through the time-based rules first, because they are the most common reason an application is premature, and then reminds you of the other conditions you will need to satisfy.
The five-year and three-year rules
Most permanent residents qualify after five years as a green card holder. There is a shorter three-year track for people who have been married to, and living with, the same US citizen for the entire three years and whose spouse has been a citizen throughout. Whichever rule applies, you can file up to 90 days early - a useful window that lets your application be in process as you reach the anniversary. The checker asks about your marital situation to decide which rule is relevant to you.
Physical presence and continuous residence
Two related but distinct tests apply. Physical presence counts the actual days you were inside the US - at least 30 months under the five-year rule or 18 months under the three-year rule. Continuous residence asks whether you kept your home in the US without long interruptions. A trip abroad of six months or more raises a presumption that continuous residence was broken, and a trip of a year or more usually breaks it outright unless you filed to preserve residence in advance. Keeping a travel log helps you prove both.
How to prepare a strong application
Beyond the timing, make sure the rest of your case is solid before you file. Demonstrate good moral character for the statutory period, which means disclosing and addressing any arrests, and ensure your taxes are filed and any owed amounts are on a payment plan. Begin studying for the civics test and practise English reading, writing and speaking, unless you qualify for an age-and-residence exemption. Gather evidence of your time in the country, your marriage if you use the three-year rule, and any name changes. Filing when you comfortably meet every requirement - rather than the earliest possible day - reduces the risk of a Request for Evidence or denial.
This checker is a simplified guide, not a decision. USCIS reviews your complete immigration and personal history, so confirm your eligibility against the official N-400 instructions or with an immigration attorney before you apply.