Five years from the date on your green card. Three years instead, if you have been married to and living with the same US citizen for all three of them. And you may send Form N-400 up to 90 days before that date arrives.
The Date That Counts Is Printed on the Card
It is the “Resident Since” date on your green card. Not the day you applied, not the day the card showed up in the mail, not the day you first entered the country. Count from that date and you have your anniversary.
The 90 Days Almost Nobody Uses
The law lets you file up to 90 calendar days before you complete the residence period. It costs nothing, and it moves your entire case roughly three months earlier — interview included. Most people never hear about it and wait for the anniversary.
Here is the trap, and it is why applications come back rejected: the 90 days only shortens the residence clock. Everything else still has to be true on the day you file. In particular, your physical presence days are counted up to the filing date, not up to the anniversary.
The Boxes That Are Easy to Forget
Days you were physically inside the United States during the 5 years — 913 of them. 18 months if you are on the 3-year track. It is a literal day count, and it is not the same thing as residence.
You have to have lived in the state or USCIS district where you file for the 3 months before filing. Moving house right before you file can cost you the filing.
You have to be 18 or older on the day you file. There are separate rules for children who become citizens through a parent.
What Quietly Resets the Clock
Trips. One trip abroad of a year or more breaks continuous residence outright, unless Form N-470 was approved before you left. A trip longer than six months but under a year is presumed to break it, and it is on you to prove otherwise — that you kept a job, a home or close family here.
Several shorter trips break nothing by themselves. They do come out of your physical presence days, one day at a time, and that is the count people forget until it is short.
The Simplest Way to Get Your Date
Not sure how many years of permanent residence you have? Our free eligibility calculator counts them for you in about ten seconds.
If the test itself is what worries you, start here: Can I Take the Citizenship Test in My Own Language?
Quick Answers
How many days before can I file Form N-400?
Up to 90 days before your 5-year (or 3-year) permanent residence anniversary, as long as you already meet the physical presence requirement on the day you file.
Is it 5 years or 3 years to apply for citizenship?
5 years for most green card holders. 3 years only if you have been married to, and living with, the same US citizen spouse for that entire period.
What is the physical presence requirement?
At least 30 months physically inside the US during the 5-year period, or 18 months during the 3-year period — a literal day count, separate from continuous residence.
What breaks continuous residence?
A single trip abroad of one year or more is generally presumed to break it. Trips of 6 months to a year may require you to prove you did not abandon your US residence.
Sources
Everything above is drawn from official U.S. government publications, which are the authority if anything here differs: