It's an uncomfortable thing to discover: a genuinely valid claim, fully documented, that can no longer be pursued simply because too much time has passed. Limitation periods exist precisely to create that cutoff, which is exactly why checking yours early — ideally before you invest real time preparing a claim — is one of the most important things you can do.
The basic limitation period
Basic limitation period
Most claims are subject to a basic 2-year limitation period under Ontario's Limitations Act, 2002.
This is the default rule that applies to most everyday disputes that fit within Small Claims Court — unpaid debts, property damage, breach of contract, and similar claims.
Why limitation periods exist at all
Limitation periods reflect a policy judgment that disputes shouldn't be able to hang over people indefinitely. Evidence fades, memories become less reliable, and it's generally considered fairer to require claims to be pursued within a reasonable window rather than allowing them to be raised many years after the fact. Whatever the fairness of this in any individual case, it's a firm structural feature of the system, not a flexible guideline.
When the clock actually starts running
The 2-year period generally runs from the day the claim was "discovered" — not necessarily the day the underlying event happened. This distinction matters, because in many disputes, the day something went wrong and the day you actually realized or should have realized you had a claim aren't the same day.
The discovery principle in practice
Generally, a claim is considered discovered on the day you first knew, or reasonably ought to have known, that: the loss or damage had occurred, it was caused by an act or omission of the person you're considering suing, and pursuing a legal claim would be an appropriate way to address it. For a debt that simply went unpaid on a known due date, discovery often lines up closely with that due date. For a defect or problem that wasn't immediately obvious, discovery may occur later, once the problem was actually identified.
Some situations can change the calculation
Certain circumstances can affect how a limitation period is calculated for a specific claim — for example, situations involving an ongoing course of conduct, or where discovering the claim was genuinely delayed through no fault of your own. Because these situations are fact-specific and can meaningfully change your actual deadline, don't try to reason through an unusual situation on your own — if anything about your timeline feels atypical, get a professional opinion promptly rather than assuming the basic rule applies cleanly.
Why checking early matters so much
Because a limitation period can expire while you're still deciding whether to pursue a claim, gathering documents, or trying to resolve things informally, it's worth checking your timeline the moment a dispute arises — not once you're finally ready to file. A claim that's otherwise strong provides no benefit if it's pursued after the deadline has passed.
What happens if the period has already expired
If a limitation period has genuinely expired, it can be raised as a complete defence to an otherwise valid claim, regardless of the claim's underlying merits — see limitation period as a defence for how a defendant would actually go about raising it. If you're unsure whether your window has closed, don't assume the worst and give up, but also don't assume you have more time than you do — get this confirmed rather than guessing, given how much rests on the answer.
Using the filing deadline calculator
The filing deadline calculator is built to give you a quick, informational estimate of when your limitation period may expire based on when your dispute arose. Treat it as a starting point for understanding your situation, and confirm anything time-critical directly given how much can turn on getting this exactly right.
Common mistakes
- Assuming the clock starts on the date of the underlying event, when discovery may have occurred later.
- Waiting to check the deadline until you're finally ready to file, rather than as soon as the dispute arises.
- Assuming an unusual situation follows the basic rule, without getting it confirmed.
- Giving up on a claim prematurely out of an unconfirmed assumption that time has run out.
Frequently asked questions
Does the 2-year period start on the date something went wrong?
Not necessarily — it generally starts on the date the claim was actually discovered, which can be later than the date of the underlying event for problems that weren't immediately obvious.
What if I'm not sure exactly when I discovered my claim?
Think through when you first knew, or reasonably should have known, about the loss and who caused it — if this is genuinely unclear, get a professional opinion rather than guessing given how much rests on the answer.
Can a limitation period ever be extended?
Certain fact-specific circumstances can affect the calculation — this isn't something to assume applies to your situation without confirming it, since the basic rule applies in most everyday disputes.
What happens if I file after my limitation period has expired?
The other side can generally raise this as a defence that can defeat an otherwise valid claim entirely, regardless of its underlying merits — this is why checking early matters so much.