United Kingdom Tax Residency Rules: The 183-Day Test
183-day threshold
How the 183-day rule works in United Kingdom
The UK uses the Statutory Residence Test (SRT), which involves day counting (183 days in the tax year April to April) plus tiebreaker tests.
Fiscal year (varies by country). The fiscal year start and end dates differ from the calendar year. Check the specific fiscal year dates for United Kingdom to know your counting window.
If you exceed 183 days, United Kingdom may tax your worldwide income as a tax resident. The exact consequences depend on your personal situation, any applicable tax treaties, and the type of income involved.
How the count works
The UK Statutory Residence Test is layered. The top of the test is automatic: spend 183 days in the UK tax year (6 April to 5 April) and you are resident, full stop. Below 183 days the SRT works through a series of automatic non resident tests, a set of automatic resident tests (the most common being having a home only in the UK), and finally a sufficient ties test that weighs family, accommodation, work, 90 day presence in previous years, and country tie. Day count thresholds within the ties test shift depending on whether you are arriving in or leaving the UK.
What counts as a day
A day counts if you were in the UK at midnight at the end of that day. There is an exception for transit passengers who do not engage in substantial work or social activity, and a separate exceptional circumstances rule that lets you discount up to 60 days a year for events like serious illness.
Beyond the day count
The sufficient ties test is where most of the complication sits. If you have several UK ties, even short stays can tip you into residency, and the thresholds change based on whether you are an "arriver" (not resident in any of the previous three tax years) or a "leaver" (resident in any of those years). Leavers face the tighter day limits.
Special tax regimes
The long standing non domicile (non dom) regime was significantly reformed in April 2025. The remittance basis was retired and replaced with a residence based regime, but new arrivals can still claim a four year exemption on foreign income and gains.
Tax treaties
UK tax treaties use the OECD tiebreaker (permanent home, centre of vital interests, habitual abode, and then nationality) when you would otherwise be resident in two countries at once.
Frequently asked questions
What counts as a UK day under the SRT?
Any day you were physically in the UK at midnight, unless you fall under the transit exception or qualify to discount the day under exceptional circumstances. The exceptional circumstances allowance is capped at 60 days a year.
What changed with non dom status in April 2025?
The remittance basis was replaced with a four year residence based regime for new arrivals. Long term non doms moved onto UK tax on worldwide income after a transition period. Existing arrangements can differ from the headline, so check with an adviser before relying on the old rules.
Does the UK tax year really run April to April?
Yes. The personal tax year is 6 April to 5 April the following year, a legacy of the 1752 calendar adjustment. Day counting follows the same window.
Official source: https://www.gov.uk/government/publications/rdr3-statutory-residence-test-srt
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