Ontario Small Claims Court Counterclaim Calculator

Counterclaim Calculator

Powered by Counterclaim Calculator by Lexscale.ai

Note: this tool is intended to provide a general, informational estimate only, based on the figures you enter. It can't assess whether your counterclaim is legally valid or how a court would actually decide either side's case — treat it as a planning aid, not a prediction of the outcome.

What this tool actually does

When you're defending a claim and believe the other side owes you money too, it's easy to think about the two amounts separately — what they're claiming, and what you think you're owed. This calculator puts both numbers side by side so you can see the net result if both claims succeeded exactly as filed, which is often a more useful way to think about your actual exposure than looking at either figure alone.

What you'll need to use it

• The amount being claimed against you in the original Plaintiff's Claim.
• The amount you believe you're owed, and a rough sense of how you arrived at that figure.
• Whether your counterclaim is genuinely connected to the same underlying dispute — see Defendant's Claims if you're unsure.

Why the net position matters more than either number alone

A defendant facing a $10,000 claim who believes they're owed $7,000 is in a very different practical position than one who believes they're owed nothing at all — even though both are "being sued for $10,000." Thinking in terms of the net outcome helps you evaluate settlement offers realistically and decide how much effort a counterclaim is actually worth pursuing.

When bringing a counterclaim makes sense

A counterclaim generally makes the most sense when your claim against the plaintiff is genuinely connected to the same dispute, well-documented, and large enough to be worth the filing fee and added effort. See Defendant's Claims for the full explanation of what qualifies and how the process works alongside the original claim.

The deadline to bring a counterclaim

A counterclaim generally needs to be filed within a specific window tied to your own deadline to respond to the original claim — see defendant deadlines. Run this calculator and make your decision promptly, since missing the window can limit your ability to bring the claim within the same case.

A worked example

Suppose you're being sued for $6,000 over an unpaid invoice, but you believe the work was defective and it will cost $2,500 to fix. Looking at the $6,000 claim alone might make the dispute feel larger than it really is; once you factor in a $2,500 counterclaim, your actual net exposure — if both sides succeeded in full — would be closer to $3,500. That reframing can change how you think about settling, defending, or how much time to invest in the case.

What this calculator doesn't tell you

This tool works from the numbers you enter — it doesn't evaluate whether your counterclaim is actually provable, whether the plaintiff's claim will succeed, or how a court might treat partial success on either side. See do I have a claim? for the underlying building blocks any claim, including a counterclaim, needs to hold up.

Next steps once you've run the numbers

If the net position makes a counterclaim worth pursuing, see Defendant's Claims for how to actually bring one, and preparing a defence for how it fits alongside your response to the original claim.

Official sources

• Rules of the Small Claims Court, O. Reg. 258/98 — the procedural rules governing claims, defences, settlement conferences, trials and enforcement.
• ontario.ca: Suing Someone in Small Claims Court — the official overview, including the current monetary limit.

Frequently asked questions