Substantial Presence Test Calculator
Find out if you are a US tax resident under the IRS 183-day weighted formula. Enter your days present in the US for the current year and the two prior years - the result updates live. Free, no signup required to calculate.
The Substantial Presence Test (SPT) determines whether a non-US citizen without a green card is a US tax resident for the year. The formula weights days over a three-year window: current year + prior year / 3 + two years ago / 6. A weighted total of 183 or more, with at least 31 days in the current year, makes you a resident alien taxed on worldwide income. Below that, you are a nonresident alien taxed only on US-source income.
Current calendar year, excluding exempt-individual days.
Weighted at 1/3.
Weighted at 1/6.
Enter your days present in the US for the current year and the two prior years to see your Substantial Presence Test result.
Track this automatically
Save your US presence days and get alerts before you cross the 183-day threshold. Free forever for one jurisdiction.
Exceptions to the Substantial Presence Test
Even if your weighted days meet the 183-day threshold, two exceptions can keep you a nonresident:
- Closer Connection Exception (Form 8840). If you are present in the US fewer than 183 days in the current year, have a tax home in another country, and maintain a closer connection to that country than to the US (family, voter registration, driver's license, banking), you can claim nonresident status.
- Exempt individuals. Diplomats (A/G visas), students on F/J visas under 5 years, teachers/trainees on J visas under 2 years, and professional athletes for competition days do not count their days toward the SPT. Students file Form 8843 to claim this status.
Green-card holders are US tax residents regardless of days present - the SPT does not apply to them.
Frequently asked questions
What is the Substantial Presence Test?
The Substantial Presence Test is the IRS formula (IRC section 7701(b)(3)) that decides whether a non-US alien is treated as a US tax resident for the calendar year. It sums days present in the US over a three-year window, weighting prior years at 1/3 and 1/6. A weighted total of 183 or more (with at least 31 days in the current year) makes you a resident alien, taxed on worldwide income.
How is the SPT weighted sum calculated?
Weighted days = days present this year + floor(days present last year / 3) + floor(days present two years ago / 6). The floor means partial contributions are rounded down, never up.
What happens if I meet the SPT?
You are generally a US tax resident for that year and taxed on worldwide income like a citizen. You may still claim nonresident status under the Closer Connection Exception by filing Form 8840 if your tax home and closer connections are in another country.
Which days do not count toward the SPT?
Days in transit under 24 hours, and days as an 'exempt individual' (A/G visa diplomats, F/J students under 5 years, J teachers/trainees under 2 years, professional athletes for competition days). Subtract those before entering your numbers. Green-card holders are residents regardless of days present.
Related tools and guides
This calculator is general information, not tax advice. Confirm your residency status with a CPA or tax attorney for your specific situation.