Does Interest Accrue on Child Support Arrears in Ontario?

If support has gone unpaid, one of the first questions is whether the debt grows. Many payors assume the arrears are a fixed number. Many recipients assume interest is added automatically. The real answer depends on what your order says and when it was made.

This article explains how interest on child support arrears generally works in Ontario, what the Family Responsibility Office (FRO) does and does not collect, and what to do if you think the balance is wrong. It is general information, not advice on your own file.

When interest can be claimed on arrears

Interest on arrears is claimed using the Statement of Arrears form. It can be claimed if the order states an interest rate.

If the order has no interest provision, interest may still be claimed under the Courts of Justice Act and the Family Law Rules, but only for orders made on or after a set date that depends on the court.

So the first step is to look at your order. Does it mention interest? If not, which court made it, and on what date?

What rate applies?

If your order states a rate, that is the starting point. If it does not, the rate depends on the rules that apply to your order, and a lawyer can confirm which one fits your situation.

For general context, Ontario publishes interest rates for court matters. The postjudgment interest rate is 4.0% for every quarter of 2026, and the prejudgment rate for the fourth quarter of 2026 is 2.5% for causes of action arising after October 23, 1989. Do not assume either figure is the rate on your arrears. Which rate applies, and from when, depends on your order and the facts.

What FRO collects and what it does not

FRO takes enforcement action only on interest that accrued because the payor failed to comply with the order. In plain words, interest connected to missed payments can be enforced, but interest that has nothing to do with non-compliance is not something FRO will chase.

FRO reviews a submitted Statement of Arrears and adjusts the balance in about 30 days. That means the number you see today may change after a recipient files one.

• Recipients: interest is not automatic just because payments were late. It is claimed through the Statement of Arrears.
• Payors: ask what the interest figure is based on. Is there a rate in the order, or is it claimed under the default rules?
• Both: FRO enforces only interest tied to the payor's failure to comply.

Can arrears or interest be reduced?

FRO cannot reduce or forgive arrears itself. It enforces the order as written. Reducing or cancelling arrears requires a court to vary or rescind the order, or a written agreement from the recipient filed with FRO. Only a judge can change the amount of support in an order.

Under the Divorce Act, a court can vary support retroactively or prospectively, and a change of circumstances is required before child support is varied. The Supreme Court has set a framework for retroactive decreases: the payor must show a past change in circumstances, and there is a presumption in favour of decreasing support back to the date the recipient received effective notice, capped at three years before formal notice. Bad faith and lack of disclosure weigh against the payor. Whether that framework helps you depends on the facts, so get advice before relying on it.

What to do next

• Find your order or agreement and check whether it states an interest rate.
• Note the court that made the order and the date it was made.
• Request or review FRO's current arrears figure and look for any interest included in it.
• If you are behind, contact FRO right away. FRO offers a voluntary arrears payment schedule, which involves a proposal form and a financial statement.
• If the amount of support itself is wrong or your circumstances changed, speak to a lawyer about applying to a court, since FRO cannot change it.
• Keep records of every payment you make or receive.

Frequently asked questions