About this site

Purpose of this site

The Substantial Presence Test (SPT) Calculator is a free, independent tool that helps you find out whether you count as a US tax resident based on the days you spent in the United States. Many visa holders and frequent visitors become US tax residents without realising it, which changes how their worldwide income is taxed.

The test is not a simple day-count. It weights the current year fully, the prior year by one third, and the year before that by one sixth — and you meet it if the weighted total reaches 183 days (with at least 31 days this year). This tool does that weighted maths for you.

How it works

The calculator runs entirely in your browser. It applies the SPT formula across three years and flags the 31-day and 183-day thresholds. It does not assess exemptions (such as exempt-individual days for certain students and visa categories) or the closer-connection exception — those need professional review.

Independent and neutral

This is an independently operated site that builds simple tools to remove the friction from complex US tax rules. We are not affiliated with the IRS, and the calculator does not collect or store your dates — everything is processed locally in your browser.

Before you rely on it

The result is an informational estimate, not tax advice, and exemptions can change the outcome. Please review our disclaimer and consult a qualified US tax professional.