The 183-day rule: how visits turn into US tax residence.
The number is 183, but the count is not what most people assume. The substantial presence test weights three years of days, and crossing it makes you a US tax resident on worldwide income — not just on what you earned there.
Figures on this page are stated for tax year 2025/26 UK · 2025 US. Thresholds change annually.
A weighted count, not a calendar one
Add all your US days this year, a third of last year's, and a sixth of the year before. Reach 183, with at least 31 days in the current year, and you meet the test. Sustained across three years, that works out at roughly 122 days annually — well within the range of a frequent business visitor.
Arrival and departure days each count as whole days. A connecting flight does not: a layover of under 24 hours between two places outside the US is expressly excluded, so frequent connectors are not accumulating days. Certain visa categories — students, teachers, diplomats — are exempt individuals whose days do not count at all, but the exemption requires its own filing.
- Current-year days + ⅓ prior year + ⅙ year before, 183 to trigger
- Minimum 31 days in the current year for the test to apply
- Green Card holders are resident regardless of day count
Over the line is not the end
Two routes out exist. The closer connection exception on Form 8840 applies where you were in the US fewer than 183 days this year alone and maintain a tax home and stronger ties abroad. The treaty tie-breaker on Form 8833 resolves dual residence in favour of one country by permanent home, centre of vital interests and habitual abode.
Both must be claimed on time, on the right form. Neither is automatic, and a late claim is frequently a lost one — which is why day counts near the boundary deserve a diary rather than an estimate.
Questions we get about this
Not necessarily. The test weights the two previous years too, so 150 days this year plus similar counts before can push the total past 183.
Run the full three-year formula rather than looking at the current year alone.
You are taxed as a US person on worldwide income - UK salary, rental profit, investments and gains all come into scope, along with FBAR and FATCA reporting.
It is a much bigger consequence than paying US tax on US-source earnings.
No, and conflating them causes real errors. The UK statutory residence test has its own automatic tests and a sufficient-ties table where the day allowance can be as low as 16.
You can be resident in both countries at once, which is what the treaty tie-breaker exists to resolve.
A simple travel diary with arrival and departure dates, backed by boarding passes and passport stamps.
Border records can be requested, but reconstructing years of travel after the fact is far harder than logging it as you go.
Last reviewed · Figures stated for tax year 2025/26 UK · 2025 US. Thresholds and rates change annually — check figures against the current tax year before relying on them.
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