Common-Law vs. Married in Canada: What Actually Changes Legally

Where common-law and married are treated the same

• The CRA generally treats common-law and married couples the same way for tax filing, the GST/HST credit, and the Canada Child Benefit, once the common-law threshold is met
• Both statuses affect eligibility for spousal-related benefits and credits in roughly the same way
• Both are expected to be reported to the CRA as soon as the relationship status actually changes — this isn't optional, and it affects benefit calculations

Where they're genuinely different — property

This is the part that surprises people. Married spouses generally have an automatic right to an equal division of family property if the relationship ends. Common-law partners often don't get that automatically — in several provinces, a common-law partner has to actively prove a claim (commonly called unjust enrichment) to get a share of property that isn't in their name, rather than starting from an assumed equal split.

It depends heavily on your province

This is not a small technicality — it's a genuinely different legal starting point depending on where you live.

• Ontario: common-law partners do not automatically share property rights the way married couples do. Property generally belongs to whoever bought it or holds title, and a common-law partner without their name on an asset may need to make a legal claim to get any share of it.
• British Columbia: the opposite approach — under BC's Family Law Act, partners who've lived together in a marriage-like relationship for at least two years are treated essentially the same as married spouses for property division, with an automatic right to an equal share of family property.
• Other provinces fall on a spectrum between these two approaches — the takeaway isn't a specific rule to memorize, it's that you genuinely cannot assume your common-law status works the same way it would in a different province.

How to protect yourself either way

• A cohabitation agreement (the common-law equivalent of a prenuptial agreement) is worth considering regardless of which province you're in — it lets you define property division terms explicitly instead of relying on default provincial rules that may not reflect what either of you actually wants
• This matters most before a major joint purchase, like a home, where the default rules in your specific province will otherwise decide the outcome
• Keep records of who paid for what, especially for anything significant — in provinces where you'd need to prove a claim, documentation is what a claim is built on
• This is genuinely provincial family law, not a general rule — a family lawyer in your specific province is worth the conversation before assuming how your situation would actually play out