US Naturalisation: The 30-Month Physical Presence Requirement
At least 913 days inside the United States during the five years before you file Form N-400. Here is how the count works.
Last verified: September 2026
In short: naturalisation under INA 316(a) requires at least 30 months (913 days) of physical presence in the United States during the five years immediately before you file Form N-400. USCIS counts the day you leave and the day you come back as days of presence. It is a target to reach, and it is separate from the continuous-residence requirement.
- Threshold
- At least 30 months (913 days)
- Counting window
- The five years before filing Form N-400
- A day counts if
- You were in the United States, travel days included
- Applies to
- Lawful permanent residents filing under INA 316(a)
- Spouse of a US citizen
- 18 months in the three years before filing
- Other conditions
- Continuous residence, plus 3 months in your state or USCIS district
- Legal basis
- INA 316(a); 8 CFR 316.2(a)(4)
The rule
Two conditions run over the same five years. Continuous residence asks whether you kept the United States as your home. Physical presence is a plain day count: at least half the qualifying period, which USCIS puts at 30 months, or 913 days. It is a number to reach, not a cap to stay under, and three points decide most cases:
- The window ends when you file. The five years run back from the day USCIS receives Form N-400, so the same travel history gives a different total depending on when you file.
- Travel days are presence. USCIS counts the day you depart from the United States and the day you return as days of physical presence, so a trip removes fewer days than its calendar span.
- Status is not evidence. A permanent resident card does not show presence by itself; USCIS expects the days to be documented.
Spouses of US citizens filing under INA 319(a) take a shorter version of the same test: 18 months of physical presence in the three years before filing.
How to count it
- Fix the date you expect to file. The window is the five years ending on that date.
- List every trip outside the United States inside that window.
- For each trip, count only the whole days between departure and return; both travel days stay on the presence side.
- Subtract the days away from the days in the window. What is left must be 913 or more.
Example. You plan to file on 1 October 2026, so the window runs 2 October 2021 to 1 October 2026: 1,826 days, including the leap day in February 2024. Reaching 913 of them leaves room for 913 days away.
Three trips abroad fall inside it. 8 January 2023 to 2 December 2023 spans 329 calendar days, but the travel days count as presence, so it removes 327. 2 February 2024 to 15 December 2024 removes 316. 12 March 2026 to 2 April 2026 removes 20.
Days away: 327 + 316 + 20 = 663. Days present: 1,826 - 663 = 1,163, clearing 913 with 250 days of the allowance unused.
The window moves with the filing date, so waiting is not automatically an improvement. Each further day in the United States adds a day at the recent end and drops one off the far end, and the total only grows when the day falling out was a day away.
Beyond the day count
Physical presence is the easiest of these conditions to measure and the least likely to decide a case alone. Continuous residence runs alongside it: an absence of more than six months but less than a year may disrupt it unless you can prove otherwise, and an absence of a year or more may disrupt it outright. You can be far past 913 days and still have broken continuous residence with one long trip. AtlasDays tracks the physical presence count; the continuous-residence condition you check yourself for now, and US green card absence limits explains how those absences are treated. USCIS also expects three months of residence in the state or USCIS district where you file.
None of this is the tax count: the substantial presence test is a separate IRS test with its own weighting and exclusions. Once a long absence, a re-entry permit, or a possibly broken qualifying period is involved, the case belongs with an immigration lawyer rather than a calculator.
AtlasDays tracks the 30-month physical presence requirement automatically
Log your trips once. The "US Naturalization Physical Presence" tracker counts every day you spent in the United States across the last 60 months, privately on your iPhone, and shows how close you are to reaching 913 days.
Get AtlasDaysFAQ
How many days do you need in the United States to naturalise?
At least 913 days, which USCIS describes as 30 months, in the five years before you file Form N-400. Spouses of US citizens under INA 319(a) need 18 months in three years.
Do the days you fly in and out count as presence?
Yes. USCIS counts both the day you depart and the day you return as days of physical presence.
Is physical presence the same as continuous residence?
No. They are separate requirements over the same period. A single absence of six months or more can disrupt continuous residence even when your total presence is far above 913 days.
About this article: AtlasDays provides general information, not legal, tax, or immigration advice. Rules change and outcomes depend on your circumstances, so never rely on it alone: check the linked official source or ask a qualified professional.