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LegalCalc Ontario
Ontario Calculator

Ontario Defendant's Claim and Counterclaim Estimator

Compare a plaintiff's claim to a proposed Defendant's Claim (Form 10A) side-by-side, calculate the ordinary 20-day filing deadline under Rule 10.01 (using the same Rule 3.01 holiday engine as the Defence Deadline Calculator), and check the $50,000 jurisdiction flag. The two claims are adjudicated separately - the net figures here are a mathematical comparison only, not set-off.

Inputs

Before you file a Defendant's Claim
  • A Defendant's Claim (Form 10A) may be brought against the plaintiff, a co-defendant, or another person the Rules permit - not against anyone the defendant wishes.
  • The ordinary issuance period is 20 days after the Defence is filed (Rule 10.01). Later filing needs leave of the court and is not automatic.
  • An issued Defendant's Claim must still be served on every party added to the case, separately from the plaintiff's own service - see Rules 8 and 10.
  • This tool does not evaluate whether the claim is meritorious or connected to the main claim; those are legal questions.

Comparison

Plaintiff
Gross claim
$0.00
Net after credits (math only)
$0.00
Defendant
Proposed gross claim
$0.00
Net after credits (math only)
$0.00
Defendant's Claim filing fee
$108.00
Jurisdiction check on defendant's claim (limit $50,000)
under

The two claims are legally distinct - the "net" figures above are arithmetic only. A judge decides liability, set-off, and judgment separately on each side.

A Defendant's Claim may be brought against the plaintiff, a co-defendant, or another person where the Rules permit. Party joinder, jurisdiction, service and relatedness of the claims all require legal analysis.

Estimate only
Calculations are estimates. Laws, rates, and rules can change. Obtain professional legal or financial advice before relying on any result.

About this calculator

In the Small Claims Court a defendant who wishes to make a claim of their own files a Defendant's Claim (Form 10A) - the equivalent of what many lawyers colloquially call a counterclaim, though the Rules use the "Defendant's Claim" terminology. Rule 10.01 requires a Defendant's Claim to be issued within 20 days after the Defence is filed, unless the court orders otherwise.

The $50,000 monetary jurisdiction applies to the defendant's own claim just as it does to the plaintiff's claim, excluding interest and costs. If the defendant's proposed claim exceeds $50,000, options include abandoning the excess or pursuing the claim in the Superior Court of Justice.

Worked example

Plaintiff sues for $15,000 and the defendant paid $2,000 before trial. The defendant proposes a $9,000 counter-claim. On a purely mathematical basis, the net to plaintiff is $13,000 and the net to defendant is $9,000. If Defence was filed on 4 May 2026, the Defendant's Claim ordinary deadline is Monday 25 May 2026 (Rule 3.01 rolls the nominal Sunday 24 May forward).

Frequently asked questions

Official sources