SPT (Substantial Presence Test)
IRS day-count test for non-citizen US tax residency. 3-year weighted formula: current + 1/3 prior + 1/6 two-years-prior ≥ 183.
The Substantial Presence Test determines US tax residency for non-citizens. You meet the SPT if (1) you were present in the US for at least 31 days in the current year, AND (2) the weighted total, current-year days + (1/3 × prior-year days) + (1/6 × two-years-prior days), is at least 183. The 3-year weighting catches non-citizens who cycle through the US year after year. Meeting the SPT triggers worldwide income taxation, unless you qualify for the closer-connection exception or apply a treaty tie-breaker.
← Browse all tax-residency terms
Track the rules these terms describe
Tax Days turns these concepts into a live day count across every US state, federal SPT, Schengen, and 200+ countries.
