Canadian tax residency is not a checkbox. It's not a day count. There is no clean "if you spent X days in Canada, you're a resident" rule the way the US has. The Canada Revenue Agency looks at whether your life is in Canada. That sounds vague because it is. This article explains how it actually works in practice, why it matters, and what to do when you're moving in or out.
Canadian residents are taxed on their worldwide income. Non-residents are only taxed on Canadian-source income (employment performed in Canada, Canadian rental property, certain pensions, etc.). The difference between the two is enormous: a wrong call here can mean filing in two countries on the same income, or missing required filings entirely.
There are two distinct paths to residency, and you only need to fall into one of them:
1. Factual residency. Your life is centered in Canada based on your "residential ties." This is the main test for most people.
2. Deemed residency. You spent 183 days or more in Canada during the year, even if your life isn't otherwise centered there. This catches people who fail the factual test but are still around enough that Canada wants to tax them.
If you fall into either bucket, you're a Canadian resident for tax purposes - unless a tax treaty (like the US-Canada treaty) overrides Canadian domestic law and breaks the tie in favor of the other country.
The CRA categorizes residential ties into two groups: significant (heavily weighted) and secondary (less weight, but they add up).
If you have any of these in Canada, the CRA's starting position is that you're probably a resident:
One significant tie is often enough on its own. Two of the three is almost always enough.
These don't usually decide a case on their own, but they paint a picture:
If you "sojourn" in Canada for 183 days or more in a calendar year, you can be deemed a resident even if your factual ties point elsewhere. "Sojourn" means temporary stay - so this catches things like extended visits, longer business trips, snowbirds going the wrong way, and digital nomads.
For dual residents, this is exactly where the treaty tie-breaker rescues you. A US person who happened to be in Canada 200 days because of a long visit to family but whose entire life is otherwise in the US would be a Canadian deemed resident under domestic law. The treaty Article IV residency tie-breaker would then override that and treat them as a US resident for treaty purposes.
For someone moving to Canada, residency typically begins on the day they establish significant residential ties - usually the move-in day. From that point forward, all worldwide income is taxable in Canada.
Income earned before the move date is generally not taxable in Canada (with some exceptions for Canadian-source income earned by non-residents, like rental income from a Canadian property). The first Canadian tax return is a part-year return covering the period from arrival to December 31.
One major step-up benefit on the way in: most assets you own when you become a Canadian resident receive a "deemed acquisition" at fair market value on the residency-start date. So if you move to Canada with $500,000 of US stock that has a $100,000 cost basis for US purposes, your Canadian cost basis starts at $500,000. If you sell later for $600,000, Canada only taxes the $100,000 of post-move gain - the US still taxes the full $500,000 historical gain, but the FTC mechanics generally handle that.
This is where most people get caught off guard. Canada has its own version of an exit tax - and it applies to ordinary residents who simply move away, not just renouncing citizens.
When you cease to be a Canadian resident, the Income Tax Act treats you as having sold most of your property at fair market value on the departure date and immediately reacquired it. You owe Canadian tax on any unrealized gain, even though no cash has changed hands.
The deemed disposition applies to most personal property and investments, including:
For larger departure-tax bills, the Canadian taxpayer can post security with the CRA and defer payment of the departure tax until they actually sell the property. This is often the right move when you don't want to liquidate to pay the tax, and it requires CRA approval and posting of acceptable security (typically a bank letter of credit or pledge of the property itself).
Departure tax is reported on Form T1243 (Deemed Disposition of Property by an Emigrant of Canada), filed with the final part-year T1 covering January 1 through the departure date. Property over $25,000 in fair market value also gets reported on Form T1161 (List of Properties by an Emigrant).
Form NR73 (Determination of Residency Status - Leaving Canada) is the CRA's optional "ruling request" form for departing residents. You fill it out, the CRA reviews your facts, and the CRA tells you whether they consider you a resident or non-resident.
Conventional wisdom in cross-border practice: do not file NR73 unless you have a specific reason to. The form invites CRA scrutiny on facts that might otherwise be unambiguous. If your departure is clean (you cut your significant ties, your family came with you, you sold or rented out the home, you're now factually in another country), you don't need a CRA ruling - you just file your final part-year return and stop filing in Canada.
NR73 makes sense when there's genuine ambiguity that you want resolved in advance: keeping a Canadian home, family staying in Canada temporarily, an unusual cross-border employment structure. In those cases, getting CRA's position before you file is helpful.
If you re-establish Canadian residency, you do so on the day your residential ties are re-established (typically move-in day). Same step-up rules apply - you get a fresh fair-market-value cost basis on most foreign assets you owned when you came back.
If you sold property at the time of departure and paid Canadian departure tax, and then come back without selling, you can elect to "unwind" the deemed disposition - effectively unmarking the original deemed sale and recovering the tax paid. This election is made on the return for the year of return.
If you are a tax resident of both Canada and the US under each country's domestic law (which happens more often than people realize), the US-Canada treaty Article IV tie-breaker decides who wins for treaty purposes. The losing country still gets its own domestic taxation, but the treaty resolves how income is allocated and credited.
Common dual-resident fact patterns:
For all of these, the residency tie-breaker (Article IV) applies sequentially: permanent home, center of vital interests, habitual abode, citizenship, mutual agreement. See the treaty article for the full mechanics.
Before you move: List every residential tie on both sides, on paper. The CRA decides residency on the totality of circumstances - the facts you can document matter more than your intent.
If you're moving out: Cut significant ties cleanly. Sell or rent out the house at arm's length on a long-term lease. Cancel the provincial health card. Close non-essential Canadian credit cards. Keep enough records to prove the move (boarding passes, utility shut-offs at the Canadian address, lease at the new country, school enrollment if children are with you).
If you're moving in: Keep a clean record of your fair market value on assets at the move-in date. This becomes your Canadian cost basis. For US persons holding RRSPs or other foreign retirement accounts, get clarity on the US side reporting requirements (FBAR, Form 8938) before you become a US tax filer.
If you're a dual citizen: Understand that a US citizen never stops being a US tax filer just by leaving the US. The treaty helps with double taxation but does not eliminate the US filing obligation.