United States tax residency: the 183-day rule
United States treats you as a tax resident at 183 days in a weighted three-year lookback — but the day count is only the part we can calculate. It is one of United States's tests, not the whole rule (see the others below). Source: Internal Revenue Service (IRS), last reviewed 2025-09-01.
183 days isn't the only route — United States can also treat you as resident on non-day grounds (green-card status (lawful permanent resident), first-year residency election). See every test below.
Add your days in United States this year, plus one-third of last year's and one-sixth of the year before. If the total reaches 183 (and you spend at least 31 days here this year), you meet the test.
Reviewed by Quentin Dupard, founder · last reviewed 2025-09-01 · How we research
- Threshold
- 183 days
- Counting window
- 3-year weighted
- Day-based test
- 1
- Last reviewed
- 2025-09-01
How does United States count days for tax residency?
According to Internal Revenue Service (IRS), you become a tax resident of United States once you spend 183 days or more there in a weighted three-year lookback. This test is weighted across three years, so being under the threshold this year is not enough on its own — days from the previous two years are added in (at one-third and one-sixth). Run the full formula before assuming you are safe.
Substantial Presence Test
183 days · a weighted three-year lookbackAdd your days in United States this year, plus one-third of last year's and one-sixth of the year before. If the total reaches 183 (and you spend at least 31 days here this year), you meet the test.
Days this year + ⅓ days last year + ⅙ days two years ago ≥ 183, AND ≥31 days this year. Closer-Connection Exception may apply. The status-based tests below apply regardless of days.
What else makes you a tax resident of United States?
The day count is only one route. United States can also make you a tax resident through any one of the following — regardless of how few days you spend there. These don't depend on a day count, so Yuravia can't track them for you; weigh them against your own situation.
Green-card status (lawful permanent resident)
If you are a lawful permanent resident (hold a green card) at any time in the year, you are a US tax resident regardless of days present — and remain taxable until the status is formally abandoned.
First-year residency election
You may elect to be treated as a resident for part of the year of arrival if you meet a presence test the following year — a voluntary route layered on the Substantial Presence Test.
United States at a glance
- Tax year
- 1 January – 31 December (calendar year). The Substantial Presence Test counts days within and across calendar years.
- How days are counted
- Any day on which you are physically present in the US at any time counts as a full day, so both arrival and departure days and any part-days count as whole days (limited exceptions apply, e.g. days in transit or as an exempt individual).
- What residency means
- US citizens, green-card holders, and resident aliens are taxed on worldwide income (citizenship-based taxation); nonresident aliens are taxed only on US-source and effectively-connected income. You become a resident under the Substantial Presence Test if present at least 31 days in the current year AND the weighted total (current year + 1/3 of prior year + 1/6 of two years before) reaches 183; dual-status rules apply in the first/last year of residency.
Official source
Internal Revenue Service (IRS). View the primary guidance ↗
Rule last checked against this source on 2025-09-01.
Count your days in United States
The day count is the one test you can actually calculate — the home, family and ties tests above, you can’t. Use a free calculator to see exactly how close you are to United States's 183-day threshold — or let Yuravia track it automatically across every country at once and warn you before you cross a line.
Frequently asked questions
How many days can I stay in United States without becoming a tax resident?
According to Internal Revenue Service (IRS), United States treats you as a tax resident at 183 days under the Substantial Presence Test (the "Substantial Presence Test"). Staying under that is necessary but not sufficient — a permanent home, family, or your centre of vital interests can make you resident on fewer days.
Is the day count the only way to become a tax resident of United States?
No. Beyond the day count, United States can treat you as resident through green-card status (lawful permanent resident), first-year residency election — any one of these can apply even if you stay well under 183 days. They don't depend on counting days, so confirm them against your own circumstances.
What counts as a day of presence in United States?
In most jurisdictions any day on which you are physically present — including the arrival and departure days — counts as a full day. Treating both as counted is the conservative assumption. Always confirm the exact rule with Internal Revenue Service (IRS).
What is the official source for United States's tax-residency rule?
Internal Revenue Service (IRS). The rule on this page was last checked against that source on 2025-09-01. Thresholds and tests change, so confirm before relying on it.
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