Free tool · IRC § 7701(b) · Substantial Presence Test

The 183-day rule calculator for Canadian snowbirds

The IRS uses a 3-year weighted formula to decide if you are a US tax resident. This calculator runs the math: current year days at full weight, prior year at one third, and the year before at one sixth. If the total reaches 183 days, you trigger the Substantial Presence Test and need to file Form 8840 (Closer Connection) to stay non-resident.

Your US presence

Days physically present in the US in the CURRENT calendar year

Days in the PREVIOUS calendar year (counts as 1/3)

Days in the YEAR BEFORE THAT (counts as 1/6)

How the math works. A day in the US is any 24-hour period during which you are physically present, including arrival and departure days. The 3-year weighted total combines current-year days at 100 %, prior-year days at 33.33 %, and the year-before-prior days at 16.67 %. If the total reaches 183, you are presumed to be a US tax resident under IRC § 7701(b)(3), regardless of immigration status.

Hard cap. Even if the 3-year total stays below 183, you become a US tax resident automatically if you spend 183 days or more in the US in the current calendar year alone. Form 8840 cannot rescue this case.

Substantial Presence result

Status — you do not trigger SPTBelow the 183-day threshold. You should still file Form 8840 yearly if you spent more than 30 days to formalize the closer-connection claim.

3-year weighted total—

SPT threshold183

Margin—

Action. If your weighted total is 183 or more, file Form 8840 — Closer Connection Exception by April 15 of the following year (June 15 with automatic extension). Without Form 8840, you are deemed a US tax resident, with full worldwide reporting (FBAR, FATCA, Form 1040, etc.).

Read the full guide: Substantial Presence Test, 183-day rule and Form 8840 for Canadian snowbirds.

Disclaimer

This calculator is for educational purpose only. It implements the basic Substantial Presence Test formula in IRC § 7701(b)(3). It does not consider exempt-individual status (students, diplomats, professional athletes), the medical-condition exemption, or the closer-connection factors that the IRS examines when reviewing Form 8840.

For any concrete decision, consult a cross-border tax attorney or a Canada-US CPA. The Form 8840 closer-connection analysis is fact-intensive and requires a qualified opinion.