Tax residency guides for the
183-day rule, SPT, Schengen & more
Plain-English explanations of the rules that decide where you owe tax. Written for individuals — not corporate tax departments.
All posts
- US States9 min read
The snowbird tax tracker guide: NY ↔ FL, NJ ↔ FL, IL ↔ FL
If you split time between a high-tax state (NY, NJ, IL, CT) and a no-tax state (FL, TX, TN), one missed day can cost you tens of thousands in state income tax. Here's how snowbirds keep their domicile claim airtight.
Read the guide → - Federal10 min read
The Substantial Presence Test, calculated step-by-step
The IRS Substantial Presence Test (SPT) is a 3-year weighted formula that determines whether non-citizens are US tax residents. Here's the formula, exemptions, and how to calculate it correctly.
Read the guide → - International8 min read
Schengen 90/180 explained: rolling windows, non-EU citizens, and how to count
The Schengen 90/180 rule is the most misunderstood tax and immigration rule in Europe. Here's how the rolling 180-day window works, with examples and a calculator-style worked example.
Read the guide → - US States11 min read
The New York 184-day rule: a survivor's guide
New York's 184-day + permanent place of abode rule is one of the most aggressively audited residency tests in the world. Here's how it works, what triggers an audit, and how to defend yourself.
Read the guide → - Guides9 min read
The 183-day rule, explained: how tax residency really works
A plain-English guide to the 183-day rule used by most countries. How a 'day' is counted, what triggers tax residency, and where the rule has surprising twists.
Read the guide →