Small Claims Court Filing Deadline Calculator (Ontario)

Filing Deadline Calculator

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Note: this tool is intended to provide a general, informational estimate only. It isn't legal advice, it can't account for every exception that might apply to your specific facts, and it doesn't guarantee any outcome. Use it as a starting point for your own research, not a final answer.

What you'll need to use it

When the calculator is live, expect it to ask for a small set of dates and details so it can give you a meaningful estimate rather than a generic answer:

• The date the underlying event happened (for example, when work was completed, or when a payment was due).
• The date you actually discovered, or reasonably should have discovered, the problem — if different from the event date.
• Whether the other side has acknowledged the debt or issue in writing since then.
• The general type of claim (for example, an unpaid debt, property damage, or a contract dispute), since some categories are treated differently.

Having these on hand before you start will make the output far more useful — and they're the same details worth writing down for your own records regardless of the tool.

Why your filing deadline matters

Ontario law puts a time limit on most civil claims. If you file after that deadline, the court can dismiss your claim outright — regardless of how much money you're owed or how clearly the other side is at fault. Unlike many court deadlines, this one generally can't be fixed after the fact, which makes it worth checking early rather than assuming you have plenty of time.

It's also easy to underestimate how much time preparation actually takes. Gathering documents, drafting a clear account of what happened, and deciding where to file can stretch on for weeks — time that eats directly into whatever runway you have left before your deadline.

How the limitation period clock works

That distinction, known as "discoverability," matters in practice. If a contractor's faulty work isn't obvious until months after the job, your clock may start when you reasonably discovered the problem, not the day they finished the job. This works in your favour in some cases and against you in others, so it's worth thinking through carefully rather than assuming either direction.

Discoverability in practice: three examples

The gap between "when it happened" and "when you discovered it" is easiest to understand through real scenarios. These are illustrative, not legal conclusions about your specific situation.

• Unpaid invoice. You invoice a client on a set date with clear payment terms. In most straightforward cases, you know about the non-payment as soon as the due date passes without payment — so the discovery date and the event date are close together.
• Defective renovation work. A contractor finishes a bathroom renovation in March. A leak caused by poor waterproofing doesn't show up until August, when it damages the floor below. Your clock may run from when you discovered (or reasonably should have discovered) the defect — around August — not from the March completion date.
• A private vehicle sale with hidden damage. You buy a used car in January. In November, a mechanic discovers frame damage that was concealed at the time of sale and wasn't reasonably visible during a normal inspection. Depending on the facts, your clock may run from November rather than January.

Notice the pattern: the more hidden or gradual the problem, the more discoverability matters, and the more worth documenting your discovery date becomes.

How to estimate your deadline manually

1. Identify your discovery date. The day you first knew, or a reasonable person in your position should have known, that you had a claim worth pursuing — not necessarily the day the underlying event occurred.
2. Add roughly two years to that date. This gives you a rough estimate of your basic limitation deadline under the general rule.
3. Check whether anything might move that date. A written acknowledgment of the debt from the other side, ongoing settlement discussions, or the specific type of claim can all matter — see the exceptions below.
4. Build in a real buffer. Treat your estimated date as a hard deadline that you aim to beat by weeks, not days — court processing time, gathering documents, and unexpected delays all eat into your runway.

What can change your deadline

• When you actually discovered the loss, as opposed to when it happened — this can move your effective start date later, sometimes by months or longer, depending on how gradually the problem became apparent.
• Attempts to resolve the matter, such as a written acknowledgment of the debt by the other side, can affect how the timeline is calculated in some situations — which is one more reason to keep any such communication in writing.
• The type of claim. Some categories of claims are subject to different rules or timelines than the general basic period, so don't assume every dispute follows the same clock.
• Longer-term limits. Beyond the basic period, other rules can apply depending on how much time has passed since the underlying event — this is a separate question from discoverability and is worth checking specifically for disputes that go back several years or more.
• Personal circumstances at the relevant time. Certain personal circumstances can affect how a limitation period is calculated — this is a narrower, fact-specific exception, so confirm directly if you think it might apply rather than assuming either way.

See Ontario limitation periods for a fuller explanation of how these exceptions work.

What happens if you miss it

If you file after your limitation period has expired, the defendant can raise that as a defence, and the court can dismiss your claim without ever considering whether you were otherwise right. There's generally no fee refund and no simple way to reset the clock — which is exactly why confirming your deadline early is worth the effort.

Close to your deadline? Do this

• Don't wait to finish gathering every document. File based on what you have — a claim can often still be refined after filing.
• Confirm your discovery date in writing — write down, with dates, when you first knew about the problem, in case it's relevant later.
• Consider filing now and negotiating in parallel — filing preserves your position; you can still settle afterward.
• If you're unsure whether you're already past the deadline, get that specific question answered rather than assuming you're too late.

How to confirm your exact deadline

Because discoverability and the various exceptions depend heavily on your specific facts, treat any general estimate — including a calculator's output — as a starting point, not a final answer. If your situation is close to a deadline, complex, or involves an older event, it's worth getting a specific answer for your circumstances rather than relying on general rules alone.

Official sources

• Limitations Act, 2002 — the law governing how long you generally have to sue.
• Rules of the Small Claims Court, O. Reg. 258/98 — the procedural rules governing claims, defences, settlement conferences, trials and enforcement.

Frequently asked questions