Guides & how-tos
Tax residency, day counting, and the rules that catch people out.
Clear, practical guides to the day-count rules that decide where you owe tax - and exactly how to track each one automatically with Tax Residency Tracker on iPhone.
US Residency
Substantial Presence Test Calculator: US Tax Residency Explained
How the IRS Substantial Presence Test works - the weighted 3-year day count, the 31-day and 183-day thresholds, exempt individuals and exceptions, and how to calculate it automatically on iPhone.
US Residency
How to Track US State Residency for Taxes
How US state residency really works - statutory residency vs domicile, the 183-day day count, why the burden of proof is on you, and how to track your days by state automatically on iPhone.
US Residency
The California 183-Day Rule and Residency, Explained
Does California have a 183-day rule? How California residency really works - the facts-and-circumstances test, the nine-month presumption, the narrow six-month presumption, the 546-day safe harbor, and how to document your days on iPhone.
US Residency
New York's 183-Day Rule and Statutory Residency
How New York's 183-day statutory-residency rule works - the 184-day line, the permanent-place-of-abode test, how any part of a day counts, and how to keep audit-proof records on iPhone.