If you’re thinking about suing someone in Ontario, the first question is always the same: how much time do I have? The answer comes from the Limitations Act, 2002, and it’s more complicated than most people think.

The Two Clocks Running Against You

Ontario doesn’t have one limitation period. It has two, running simultaneously. The basic period gives you two years from the date you discovered (or should have discovered) your claim under s. 4. The ultimate period gives you fifteen years from the date of the act or omission under s. 15, regardless of when you discovered it. Your actual deadline is whichever expires first.

Most legal blogs stop there. But calculating your real deadline requires working through several additional questions.

When Did You Actually “Discover” Your Claim?

The two-year clock doesn’t necessarily start on the day the event happened. Section 5 defines discovery as the day you first knew, or ought to have known, that you suffered a loss caused by someone else’s act or omission and that a legal proceeding would be an appropriate remedy. However, there’s a catch: s. 5(2) creates a presumption that you discovered the claim on the day the event occurred. If you want to argue a later discovery date, the burden is on you to prove it.

Factors That Can Pause or Reset the Clock

Several things can suspend or extend your limitation period. If the claimant was a minor at the time of discovery, the clock may be paused under s. 6. Incapacity under s. 7 can also suspend the running of the basic period, with a minimum six-month window after capacity is regained. If the parties attempted mediation or another alternative dispute resolution process, s. 11 suspends the period during that process. A written tolling agreement under s. 22 can also pause the clock by consent.

One factor that catches people off guard is acknowledgment under s. 13. If the person who owes the obligation acknowledges liability in writing before the limitation period expires, the clock resets entirely — as if the act or omission happened on the date of the acknowledgment. But this only works if the acknowledgment is made before the existing period runs out, per s. 13(9).

There’s also the COVID-19 emergency suspension under O. Reg. 73/20, which froze limitation periods between March 16 and September 13, 2020.

Why This Matters

These factors don’t just add complexity. They interact with each other. Suspension periods can overlap, acknowledgments can erase prior suspensions, and the ultimate period has its own separate set of tolling rules. Getting it wrong by even a day can mean losing your right to sue entirely, or defending against a claim you thought was long dead.

Calculate Your Deadline

We built a free Ontario Limitation Period Calculator that walks you through each of these factors step by step and shows you exactly how your deadline is calculated, with full statutory references. It accounts for discovery dates, suspensions, acknowledgments, the COVID-19 freeze, tolling agreements, and even holiday extensions under the Legislation Act, 2006.

Try the Ontario Limitation Period Calculator.

This article is for general informational purposes only and does not constitute legal advice. If you have questions about your limitation period or legal rights, you should consult a licensed lawyer in Ontario.

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