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US Naturalization Days Calculator – free online
Enter the date you became a permanent resident and your trips outside the US. See your days in the US, the trips long enough to be flagged, and the earliest date you could file Form N-400 under the 5-year and 3-year rules.
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Count your days
Your trips outside the United States
One row per trip: the day you left and the day you came back. Travel days are not counted as days outside the US. Dates are year-month-day, and the date is shown below each box in the form 15 Oct 2026.
Worked example
An invented example. A person became a permanent resident on 15 Mar 2021 and uses the 5-year rule. They want to check their situation on 20 Jun 2026. They took four trips abroad.
| Left the US | Came back | Days counted outside | Flag |
|---|---|---|---|
| 18 Dec 2021 | 5 Jan 2022 | 17 | none |
| 1 Jul 2022 | 22 Jul 2022 | 20 | none |
| 1 Oct 2024 | 20 Apr 2025 | 200 | more than 180 days: presumed to break continuity unless the person shows it did not |
| 2 Aug 2025 | 12 Aug 2025 | 9 | none |
- The 5-year residence period was complete on 15 Mar 2026. The earliest filing date under the 5-year rule is 15 Dec 2025 (90 days earlier).
- Period examined: 20 Jun 2021 to 20 Jun 2026, which is 1,827 days.
- Days outside the US in that period: 17 + 20 + 200 + 9 = 246. Days in the US: 1,827 − 246 = 1,581.
- 913 days are required, so there are 668 days to spare. The 200-day trip still needs to be explained.
Press "Load the example" above to see the calculator give the same numbers.
How it works
The rules, from USCIS
- Residence period. 5 years of continuous residence as a permanent resident (INA 316), or 3 years for certain spouses of U.S. citizens (INA 319(a)). Source: Policy Manual, Volume 12, Part D, Chapter 3, and the Form N-400 instructions.
- Physical presence. At least half of the period: 913 days in the past 5 years, or 548 days in the past 3 years. The day you leave and the day you return count as days in the US. Source: Volume 12, Part D, Chapter 4 (913 days), Volume 12, Part G, Chapter 3 (548 days) and the N-400 instructions (table of physical presence requirements).
- Travel days. USCIS does not count the dates of travel among the days outside the United States: the first day counted outside is the day after you leave and the last is the day before you come back. Source: Chapter 3, footnote to the example.
- Long trips. More than 180 days and fewer than 365 days: presumed to break continuity. 365 days or more: breaks continuity unless Form N-470 applies. Source: Chapter 3 and the N-400 instructions.
- Period measured back from the filing date. The Policy Manual says the statutory period is calculated from the date of filing. Source: Chapter 3.
- Early filing. Up to 90 days before the period is complete; you cannot be naturalized before it is complete. USCIS counts back 90 days from the day before the period would first be satisfied. Source: Volume 12, Part D, Chapter 6 (5-year route) and the N-400 instructions, section "Early Filing" (5-year and 3-year routes).
Also see the USCIS Form N-400 page. The edition of the N-400 instructions we read is dated 01/20/25. Date checked: 26 October 2026.
How this calculator applies them
- Days outside the US: for each trip, every day between the day you left and the day you came back, not including those two days. Overlapping trips are counted once.
- Period examined: it starts on the same calendar date 5 (or 3) years before the date you are testing, and ends on that date. This follows the Policy Manual's own example, in which a filing on January 3, 2015 looks back to January 3, 2010. It never starts before your permanent resident date. Days in the US are the days of that period minus the days outside.
- Trip flags are based on the days of the trip that fall inside the period examined.
- Earliest filing date: the date the residence period is complete minus 90 days. Check against the Policy Manual example: complete on 10 Jun 2010 gives 12 Mar 2010.
Not confirmed on an official page
- The Policy Manual does not say, step by step, which day the 5-year (or 3-year) period is first satisfied. This calculator takes the 5th (or 3rd) anniversary of your permanent resident date. For a date such as 29 Feb, or if you are near the limit, compare the result with USCIS's own tools and with the USCIS pages above.
- The pages do not spell out the exact first day of the period used to count physical presence. We use the same first day as for continuous residence, so a result can be off by one day at the edge.
What this calculator does not do
- It does not check good moral character, English, civics, the 3 months in your state or USCIS district, the marriage conditions of the 3-year route, Form N-470, military or other special cases, or when you may apply again after a break in continuous residence.
- It does not show fees or processing times. USCIS decides every case.
Frequently asked questions
How long must I be a permanent resident before I can apply for naturalization?
Generally 5 years of continuous residence after you became a lawful permanent resident. If you apply as the spouse of a U.S. citizen, the period is 3 years. For the 3-year route, the USCIS instructions say you must have been married to a U.S. citizen for at least 3 years when you file, and the Policy Manual adds that you must have lived in marital union with your citizen spouse for those 3 years and that your spouse must have been a citizen for those 3 years. You must also have lived for at least 3 months in the state or USCIS district where you file.
Can I file Form N-400 before the 5 years (or 3 years) are complete?
Generally yes, up to 90 days before you complete the required period of continuous residence. The USCIS N-400 page says 90 calendar days, for both the 5-year and the 3-year route. Filing early does not make you eligible sooner: you cannot be naturalized until the full period is reached, and the N-400 instructions say you must still meet all other requirements at the time of filing. USCIS's Policy Manual says it counts back 90 days from the day before the period would first be satisfied. Its example: if the five-year requirement is first met on June 10, 2010, the earliest filing date is March 12, 2010.
How many days must I be physically in the United States?
At least half of the required period. For the 5-year route that is 30 months (913 days) during the past 5 years. For the 3-year route (spouse of a U.S. citizen) it is 18 months (548 days) during the past 3 years. USCIS counts both the day you leave the United States and the day you come back as days in the United States. Physical presence and continuous residence are two separate requirements, and you must meet both.
How long a trip abroad can break my continuous residence?
Under the Policy Manual, an absence of more than 180 days but fewer than 365 days during the period is presumed to break continuity, and you can try to rebut that presumption with evidence (for example that you kept your U.S. job, your immediate family stayed in the U.S., or you kept access to your U.S. home). An absence of 365 days or more breaks continuous residence, unless you have an approved Form N-470 (Application to Preserve Residence for Naturalization Purposes), which is only available in certain situations such as qualifying employment abroad.
Are the day I leave and the day I return counted as days abroad?
No. The Policy Manual says USCIS does not count the dates of travel among the days spent outside the United States. In its example, a person who leaves on January 1, 2010 and returns on January 2, 2011 has January 2, 2010 as the first day counted outside and January 1, 2011 as the last. This calculator counts days outside the same way.
Which trips do I have to list on Form N-400?
The instructions say to list all the trips you have taken outside the United States during the last 5 years if you apply under the general provision, and during the last 3 years if you apply on the basis of marriage to a U.S. citizen. Always read the current instructions for the edition of the form you use.
Sources read and checked on 26 October 2026. USCIS rules and forms change, so check the official pages before you file. This tool is independent and is not affiliated with USCIS or any government. See the disclaimer.