Guides · reviewed 2026-09-04

Interest: what you can claim and how to calculate it

Legal information, not legal advice. Results depend on the facts of your case.

Legal information, not legal advice. This guide and our free tools give legal information. They do not give advice about your case. A licensed lawyer can give legal advice.

The answer

You can claim interest on the money owed, from the day the claim arose until the day of the judgment. If your contract sets a rate and the other side agreed to it, that rate applies. If not, the court rates apply.

The rates (2026)

Case started in Prejudgment rate Judgment made in Postjudgment rate
Q1 2026 (Jan–Mar) 2.5% Q1 2026 4.0%
Q2 2026 (Apr–Jun) 2.5% Q2 2026 4.0%
Q3 2026 (Jul–Sep) 2.5% Q3 2026 4.0%
Q4 2026 (Oct–Dec) 2.5% Q4 2026 4.0%

For cases started in Q4 2025 (October to December 2025), the prejudgment rate is 3.0%. The rates for 2027 are not published yet. The province publishes each quarter's rates after the first day of the last month of the quarter before.

How the rates work

  • The quarter in which you start the case sets your prejudgment rate for the whole case.
  • The quarter in which the court makes the order sets the postjudgment rate.
  • Prejudgment interest runs from the day the claim arose to the day of the order.
  • Postjudgment interest runs on the money owed under the order, including costs, from the date of the order until payment.
  • No prejudgment interest on punitive damages, on interest, on costs, or on a consent order unless the debtor agrees.
  • The judge can refuse interest, or set a different rate or period, when that is just.

A simple example

You claim $10,000. The claim arose exactly 1 year before judgment. You started the case in 2026, so the court rate is 2.5%.

  • Interest = $10,000 x 2.5% x 1 year = $250.
  • The judgment can be $10,250, plus costs.
  • For part of a year: amount x rate x days ÷ 365.

What to do

  1. Check your contract for an interest rate the other side agreed to.
  2. If it has one, claim that rate on Form 7A and attach the contract.
  3. If it does not, choose the Courts of Justice Act rate on Form 7A.
  4. Write the date the claim arose. Interest runs from that date.
  5. Bring a simple calculation to court: amount x rate x days ÷ 365.

Good to know

  • The $50,000 limit does not include interest and costs.
  • The rates change each quarter. Check the current rate before you file.
  • After judgment, add postjudgment interest until the defendant pays. A certificate of judgment states the rate.

Common mistakes

  • Do not leave the interest section empty on Form 7A.
  • Do not start the interest on the day you file. It runs from the day the claim arose.
  • Do not use an old rate. Use the rate for the quarter you start the case.
  • Do not claim a contract rate with no proof. The rate must be in the agreement.

When to get a lawyer

Get legal advice if the interest terms in your contract are not clear. Legal services provided by Mithril Law — Jonathan Kleiman, licensed Ontario lawyer.

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