How Child Support Is Calculated in Ontario

In Ontario, child support is usually set by the Federal Child Support Guidelines. The basic monthly amount comes from a table that looks at the paying parent’s income, the number of children and the province where the paying parent lives. Some extra costs, like child care, can be added on top and shared between both parents.

What the child support table looks at

Most child support in Ontario starts with the Federal Child Support Guidelines. The Guidelines include a set of tables, one for each province and territory. Ontario uses the federal tables for all of its child support matters.

To find the basic amount, you need three things: the paying parent’s annual income, the number of children, and the province or territory where the paying parent lives. The table then gives a monthly figure. This is called the table amount.

Income is not just your salary. It starts with the sources listed under “Total income” on your T1 General tax return, and then some adjustments are made. If a parent is working less than they reasonably could, a court can impute income. That means it can treat them as earning more than they report.

The tables cover incomes up to $150,000. Above that, a court can use the full table amount or apply the table to the first $150,000 and decide a fair amount for the rest.

What happened to the tables in 2025

The federal tables were updated and took effect on October 1, 2025. The new amounts reflect changes to tax rules. They are not adjusted for inflation or the cost of living.

An order made before that date does not change automatically. If you want the new amounts to apply, you need to apply to a court or a recalculation service. The difference in the table amount may count as a change in circumstances.

Special and extraordinary expenses

Many families have costs the table amount does not cover. The Guidelines call these special or extraordinary expenses. People often call them “section 7 expenses” after the section of the Guidelines that lists them.

They can include:

• child care costs needed because the parent with most of the parenting time is working, ill, disabled, or in school or training
• the part of medical and dental insurance premiums that covers the child
• health costs that go over what insurance pays by at least $100 a year, such as orthodontics, counselling, prescription drugs or glasses
• extraordinary costs for elementary or secondary school
• costs for college or university
• extraordinary costs for extracurricular activities

A court does not add every cost automatically. It looks at whether the expense is necessary for the child’s best interests and whether it is reasonable given what the parents and child can afford.

When an expense is allowed, the parents share it in proportion to their incomes. For example, if one parent earns 60% of the combined income, that parent usually pays 60% of the cost. Any contribution from the child, such as a scholarship, comes off first.

When parenting time is shared or split

The basic table approach assumes one parent has the children most of the time. Two common situations change the math.

Shared parenting (40% or more each)

If each parent has a child for at least 40% of the parenting time over a year, the court must take into account both parents’ table amounts. It also considers the higher costs of running two homes for the children and each family’s situation.

Split parenting

Sometimes there are two or more children and each parent has most of the time with at least one of them. In that case, each parent’s table amount is worked out, and the parent with the higher amount pays the difference.

Undue hardship

Sometimes a parent or child would face serious financial difficulty if the normal amount were paid. A court can then order a different amount. This is called undue hardship. The court also compares the standard of living in each home. If the home asking for the change would still have the higher standard of living, the request must be refused.

How to set up and keep child support current

If support is part of ending a marriage, our guide on how to get a divorce in Ontario covers the court steps. Either way, Ontario gives parents three main ways to arrange child support:

Support set up online or through the court is filed automatically with the Family Responsibility Office (FRO). FRO collects the payments and passes them on. If payments are missed, it can report to credit bureaus, suspend a driver’s licence or passport, and garnish a bank account.

If you have a written agreement, you can still use FRO. You file the agreement with the court along with a Form 26B affidavit, then send a copy of the agreement to FRO.

Child support is not a one-time number. The paying parent must give proof of income every year, including their latest tax return and notice of assessment or reassessment, unless the parents agreed on a different timeframe. When special expenses are part of the support, both parents also need to share details about those costs.