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Calculate pre-judgment interest under the Courts of Justice Act using the official rate for the quarter your claim was issued, set by the Ontario Ministry of the Attorney General.
For estimation purposes only. Not legal advice. Confirm rates with the Ontario Ministry of the Attorney General.Official quarterly rates from the Courts of Justice Act will be applied automatically.
In Ontario, pre-judgment interest generally runs from the date the loss arose to the date of judgment. Unless a contract sets a different rate, it is calculated using the rate published quarterly under section 127 of the Courts of Justice Act, based on the quarter in which the proceeding began. Pre-judgment interest must be claimed in your Plaintiff's Claim, and the court may adjust or decline it under section 130.
| Year | Q1 (Jan–Mar) | Q2 (Apr–Jun) | Q3 (Jul–Sep) | Q4 (Oct–Dec) |
|---|---|---|---|---|
| 2026 | 2.50% | 2.50% | 2.50% | 2.50% |
| 2025 | 4.00% | 3.30% | 3.00% | 3.00% |
| 2024 | 5.30% | 5.30% | 5.30% | 4.80% |
| 2023 | 5.30% | 5.30% | 5.30% | 5.30% |
| 2022 | 0.50% | 1.50% | 3.50% | 4.50% |
| 2021 | 0.50% | 0.50% | 0.50% | 0.50% |
| 2020 | 2.50% | 0.50% | 0.50% | 0.50% |
| 2019 | 2.00% | 2.00% | 2.00% | 2.00% |
| 2018 | 1.50% | 1.50% | 1.50% | 2.00% |
| 2017 | 1.00% | 1.00% | 1.50% | 1.50% |
| 2016 | 1.00% | 1.00% | 1.00% | 1.00% |
| 2015 | 1.00% | 1.00% | 1.00% | 1.00% |
| 2014 | 1.00% | 1.00% | 1.00% | 1.00% |
| 2013 | 1.00% | 1.00% | 1.00% | 1.00% |
| 2012 | 1.50% | 1.50% | 1.00% | 1.00% |
| 2011 | 1.50% | 1.50% | 1.50% | 1.50% |
| 2010 | 1.00% | 1.50% | 1.50% | 1.50% |
| 2009 | 1.50% | 1.00% | 1.00% | 1.00% |
| 2008 | 4.50% | 4.00% | 3.50% | 2.50% |
| 2007 | 4.50% | 4.50% | 4.50% | 4.50% |
| 2006 | 3.50% | 4.00% | 4.00% | 4.00% |
| 2005 | 2.50% | 2.50% | 2.50% | 3.00% |
| 2004 | 3.50% | 3.50% | 3.50% | 3.50% |
| 2003 | 3.00% | 3.50% | 3.50% | 3.50% |
| 2002 | 3.00% | 3.00% | 3.00% | 3.00% |
| 2001 | 6.50% | 6.50% | 5.50% | 4.50% |
| 2000 | 6.00% | 6.00% | 6.00% | 6.00% |
Pre-judgment interest in Ontario is governed by ss. 128–130 of the Courts of Justice Act. The rate is set quarterly and published in the Ministry of the Attorney General's official rate tables.
Ontario pre-judgment interest is simple, not compound. It is calculated per day on the principal amount across the whole accrual period.
Your rate is fixed by the quarter the proceeding was commenced (the claim was issued) — s. 127. That single rate applies to the whole period from when the cause of action arose to judgment. It does not change quarter by quarter.
If a contract specifies an interest rate, that rate generally applies instead of the CJA statutory rate. Toggle the fixed-rate option above.
Prejudgment interest compensates a successful plaintiff for being kept out of their money between the day the loss arose and the day the court gives judgment. In an Ontario Small Claims Court case it is claimed in the Plaintiff's Claim and awarded under section 128 of the Courts of Justice Act, either at the statutory rate published quarterly by the Ministry of the Attorney General or at the rate the parties agreed to in their contract.
It is distinct from postjudgment interest, which starts running on the unpaid amount only after judgment is granted. A typical claim accrues prejudgment interest first, then switches to postjudgment interest from the date of the order until the debtor actually pays.
Prejudgment interest is calculated as simple interest using:
where Days is the number of days from the date the cause of action arose to the date of the order. The rate is fixed by the quarter in which the proceeding was commenced and does not change from quarter to quarter afterwards. Ontario prejudgment interest never compounds — it is simple interest on the principal only.
Interest starts on the day the cause of action arose — the day the money became owed or the loss happened, such as the due date of an unpaid invoice, the date a cheque was dishonoured, or the date property was damaged. It stops on the date of the order. For a claim for money owed under a contract with its own interest clause, the contractual start date and rate govern instead.
The single applicable rate is set by the quarter the claim was issued, not the quarter the loss occurred — so a loss from 2024 sued on in Q1 2026 uses the Q1 2026 rate for the whole period.
Under section 128(4) of the Courts of Justice Act, prejudgment interest is generally not available on:
The court also keeps a broad discretion under section 130 to allow a higher or lower rate, change the start date, or refuse interest entirely where it is just to do so — for example where a plaintiff delayed the case unreasonably.
In a personal injury action, interest on non-pecuniary (pain and suffering) damages is calculated at a fixed rate under Rule 53.10 of the Rules of Civil Procedure, rather than the quarterly Courts of Justice Act rate. If you are calculating that head of damages, use the rate-override field above.
Suppose a customer owes $20,000 on an invoice that fell due on January 15, 2026, there is no contractual interest clause, and the Small Claims Court claim was issued in Q1 2026, when the statutory rate was 2.5% per year. If judgment is granted 400 days after the invoice fell due:
The plaintiff would claim $20,000 in principal plus roughly $547.95 in prejudgment interest to the date of judgment. The court confirms the exact figure when it makes the order, so treat the result — like every output of this calculator — as an estimate rather than a fixed entitlement.
Prejudgment interest compensates a successful party for being kept out of their money between the date the cause of action arose and the date the court makes its order. In Ontario it is awarded under section 128 of the Courts of Justice Act and calculated as simple interest at the quarterly rate published by the Ministry of the Attorney General.
For the third quarter of 2026, the prejudgment interest rate in Ontario is 2.5% per annum. This is the official rate published by the Ministry of the Attorney General, and it is read from the same rate table the calculator above uses so the two stay consistent.
This calculator sets the rate using the date the claim was issued — the quarter in which the proceeding was commenced. That single rate then applies across the whole period: interest runs from the date the cause of action arose to the date of the court's order.
It is simple interest by default — it does not accrue interest on itself. Compound interest is only available in limited circumstances, such as where a contract pleaded in the claim provides for it.
No. Under section 128(4) of the Courts of Justice Act, prejudgment interest is generally not awarded on punitive or exemplary damages, on interest itself, on costs, or on the portion of an award representing pecuniary loss that arises after the date of the order.
Yes. The Small Claims Court is a branch of the Superior Court of Justice, so section 128 applies. Interest should be claimed in the Plaintiff's Claim.
It runs from the date the cause of action arose — for example, the date a contract was breached or the date a loss was suffered — up to the date of the court's order. It does not run only from the date you filed your claim.
Multiply the principal amount by the annual rate, divide by 365, and multiply by the number of days between the date the cause of action arose and the date of the order. Because it is simple interest, you do not compound it. The calculator above does this automatically using the official quarterly rate.
For most claims, a single rate applies for the whole period — the rate in effect in the quarter the proceeding was commenced. The rate does not reset each quarter as the case goes on, which is why the calculator uses the claim-issue date to set the rate.
Yes. You should plead and claim prejudgment interest in your Plaintiff's Claim or statement of claim. While courts often award it as a matter of course, the safest practice is to claim it expressly so there is no question it is on the table.
Yes. Under section 130 of the Courts of Justice Act, the court has discretion to raise or lower the rate or change the period, considering factors such as changes in market interest rates, the circumstances of the case, and the conduct of the parties (for example, unreasonable delay).
Historically a distinct rate has applied to non-pecuniary loss in personal injury cases, separate from the quarterly rate used for most other claims. If your claim includes pain-and-suffering damages, confirm which rate applies to that portion, as it can differ from the figure this calculator uses for general claims.
Yes. If a contract sets its own interest rate, that contractual rate generally governs instead of the default Courts of Justice Act rate, and compound interest may be available where the contract provides for it. Enter the applicable rate where your agreement specifies one.
Prejudgment interest compensates you for the period before the court's order (from when the cause of action arose to the date of judgment). Post-judgment interest runs after the order, on the unpaid judgment, until it is paid. They use separate rate tables and separate calculations.
No. Under section 128(4), prejudgment interest is generally not awarded on costs, on interest itself, on punitive or exemplary damages, or on the part of an award for pecuniary loss arising after the date of the order.
The calculator gives a reliable estimate for planning, but the exact interest a court awards can turn on the correct start date, the right rate for your type of claim, and the court's discretion. For anything significant it is worth having a lawyer confirm the figure and how to plead it. Our team offers a free consultation.
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