The Substantial Presence Test
IRS, Guide
How the IRS decides whether a non-citizen without a green card is a US resident for tax, and the exceptions that change the count.
The Substantial Presence Test: the short answer
A British national without a green card becomes a US tax resident by spending enough days in the US. The substantial presence test counts those days using a weighted formula across three years. Several exceptions remove days from the count or override the result.
Counting days the way the IRS does
The test has two limbs. The person must be present for at least 31 days in the current year, and the weighted total must reach 183 days.
The weighted total adds every day in the current year, one third of the days in the prior year and one sixth of the days in the year before that. A person who meets both limbs is a resident alien for the year.
Generally any part of a day in the US counts as a day of presence, but there are carve-outs. Days in transit of less than 24 hours between two places outside the US are excluded. So are days as an exempt individual, such as certain students, teachers and trainees on qualifying visas, and diplomats. Days spent unable to leave because of a medical condition that arose in the US can also be excluded.
Two separate mechanisms can then override a positive result. The closer connection exception is available to someone present for fewer than 183 days in the current year who keeps a tax home and closer connection abroad, claimed on Form 8840. The treaty tie-breaker is different: a person resident in both countries can claim treaty residence in the UK, disclosed on Form 8833, and is then taxed as a nonresident for most purposes.
At a glance
- 31 days
- Current-year minimum
- 183 days across three years
- Weighted total
- All current days, a third, then a sixth
- Weighting
- Closer connection exception and treaty tie-breaker
- Separate overrides
Figures are for the tax year stated in the official instructions linked below.
How we handle it
- Cross-Border Tax
US and UK returns prepared together from one set of workpapers, so credits, tax years and exchange rates line up across both.
- Treaty Relief
Claims under the US/UK income tax treaty, with Form 8833 disclosure, residence tie-breaker analysis and reduced withholding on US income.
- Individual Tax Returns
US federal returns for Americans living in the UK and British nationals with US income, prepared with the UK figures in view.
- Tax Planning
Forward planning across the US and UK tax systems: timing income, choosing investments, arriving, leaving and organising family finances.
Where people go wrong
The misreadings we correct most often.
Who this affects
- British nationals spending extended periods in the US each year
- UK executives commuting to US offices on business visas
- Arrivals on work visas deciding their first US tax year
- Former residents checking whether visits still create residence
01
Counting days without removing short transit stops and exempt periods
02
Treating the closer connection exception and the treaty tie-breaker as one
03
Assuming the UK Statutory Residence Test produces the same answer
04
Forgetting that treaty residence claims have their own disclosure requirements
Why US UK Tax Returns
Every form is prepared against the official instructions, and every position on it is one we can point to in the Code, the treaty or HMRC's guidance.
One File
US and UK returns prepared in the same engagement and reconciled line by line.
Primary Sources
Every position traced to the Code, the treaty, IRS instructions or HMRC guidance.
Scope First
Returns, forms, years and fee agreed in writing before work begins.
The Same People
The team that files this year carries the elections and credits into the next.
Questions we are asked
I spent about four months in the US this year. Am I a US tax resident?
It depends on the weighted total, not just this year's days. Days from the previous two years are added at one third and one sixth, so a pattern of regular long visits can cross the line even if no single year looks high. Exempt days and short transits come out first. If the test is met, the closer connection exception or the treaty may still apply.
Is the closer connection exception the same as using the treaty?
No. The closer connection exception is a domestic US rule, claimed on Form 8840, for people below the current-year limit who keep their tax home and closer ties abroad. The treaty tie-breaker applies to people resident in both countries and uses the treaty tests, with a Form 8833 disclosure where required. They have different conditions and different consequences.
If I fail the US test, does that make me non-resident in the UK as well?
No. The UK uses the Statutory Residence Test, which looks at days in the UK, ties to the UK and work patterns. It does not ask about US days in the same way. It is quite possible to be resident in both countries, or in neither, under their own rules, which is why the treaty tie-breaker exists.
Primary sources
What this page says is drawn from the official material below. Read it yourself; we would rather be checked than trusted.
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