US Substantial Presence Test Calculator
Use this US Substantial Presence Test calculator to estimate whether you meet the IRS threshold for being treated as a US resident for tax purposes. The test weights days present over three years. Enter your days in the US for the current year and the two years before, and the calculator applies the formula and tells you whether you meet the test.
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Check the Substantial Presence Test
Enter values above and press Calculate to see your result.
Formula used
The IRS Substantial Presence Test is met if both conditions hold:
1) Days this year ≥ 312) Days this year + (last year ÷ 3) + (two years ago ÷ 6) ≥ 183
So recent days count fully, the prior year counts a third, and the year before that a sixth. If the weighted total reaches 183 and you were present at least 31 days this year, you generally meet the test.
Worked examples
Equal years. 120 + 120 + 120 → 120 + 40 + 20 = 180, which is below 183 — test not met.
Heavier current year. 150 + 120 + 120 → 150 + 40 + 20 = 210 — test met.
Short visit. 25 days this year fails the 31-day minimum regardless of prior years.
How to use this calculator
- Count the days you were physically present in the US this calendar year.
- Count your days for last year and the year before.
- Enter all three.
- Press Calculate to see the weighted total and whether the test is met.
- Confirm exemptions and exceptions with a tax professional.
How each year is weighted
| Period | Weight | Example: 120 days |
|---|---|---|
| Current year | × 1 | 120 |
| Prior year | ÷ 3 | 40 |
| Two years ago | ÷ 6 | 20 |
| Threshold | — | ≥ 183 (and ≥ 31 current) |
Some days don't count (e.g. certain exempt individuals, days in transit, medical conditions).
Who should use this calculator
Non-US citizens who spend significant time in the United States — on work, study, or extended visits — and need to understand whether they might be considered US tax residents. It's a first-pass check before seeking professional advice.
Why the test matters
If you meet the Substantial Presence Test, the US may treat you as a resident for tax purposes, which generally means reporting worldwide income. The weighting of prior years catches people who spend several months in the US each year, even if no single year reaches 183 days. Getting this wrong can lead to unexpected filing obligations.
Exemptions and exceptions
- Exempt individuals — certain students (F/J/M/Q), teachers and trainees don't count their days for a period.
- Closer-connection exception — you may avoid residency if you have a tax home and closer ties to another country and were present under 183 days this year.
- Tax treaties can override the default result.
- Excluded days include some transit days and days you couldn't leave due to a medical condition.
Limitations of this calculator
This applies the basic three-year formula only. It does not account for exempt-individual status, excluded days, the closer-connection exception, dual-status years, or treaties — all of which can change the result. It is an estimate for general understanding, not tax or legal advice. Consult a qualified professional or the IRS for your situation.
Frequently asked questions
What is the Substantial Presence Test?
It's the IRS day-counting test for US tax residency. You meet it if you're present at least 31 days this year and your weighted three-year total (this year + ⅓ last year + ⅙ the year before) is at least 183.
How are prior years counted?
The current year counts fully, the prior year counts one-third, and two years ago counts one-sixth. This catches regular part-year visitors.
What does it mean if I meet the test?
You may be treated as a US tax resident and generally required to report worldwide income — though exceptions and treaties may apply. Get professional advice.
Do all days in the US count?
No. Certain exempt individuals (some students and teachers), transit days, and days you couldn't leave for medical reasons may not count.
Is this official IRS guidance?
No. It's an estimate of the formula. Confirm exemptions, exceptions and treaties with a tax professional or the IRS.