Tax-residency rule guides
The day count that decides tax residency isn't one rule — it's a family of them. These guides explain each type in plain English, show which countries use it, and link to the exact threshold and official source for every jurisdiction. Start with the rule you're up against, or browse all countries.
The 183-day rule for tax residency
What the 183-day rule really means for tax residency, why “half the year” is a myth, and the exact 183-day threshold and counting window for each country that uses it.
Read the guide →The US Substantial Presence Test
How the US Substantial Presence Test decides tax residency: the 31-day and 183-day parts, the three-year weighted formula (current + 1/3 + 1/6), and who it affects.
Read the guide →The rolling 183-day rule
Some countries count 183 days across a rolling 12-month window that never resets on 1 January. How the rolling day-count rule works and which countries use it.
Read the guide →Tax treaty tie-breaker rules
When two countries both treat you as a tax resident, a double-tax treaty’s tie-breaker decides which one wins: permanent home, centre of vital interests, habitual abode, then nationality.
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