How is child support calculated in Ontario?

By looking up the paying parent's annual income and the number of children in the Federal Child Support Guidelines table for Ontario, which produces a fixed monthly base amount. On top of that base amount, parents typically share specific add-on costs, called section 7 or 'special' expenses, like child care or extracurricular activities, in proportion to their incomes.

Do I use federal or Ontario child support rules?

Both, but they line up. The Federal Child Support Guidelines set the actual tables and formula, and apply to Divorce Act cases (married parents divorcing). Ontario has adopted essentially the same guidelines through its own Child Support Guidelines regulation (O. Reg. 391/97) under the provincial Family Law Act, which applies to unmarried or separated-but-not-divorcing parents. In practice, the table amounts and add-on rules are the same either way.

What are section 7 or 'special' expenses?

Costs beyond the base table amount: child care, health-related expenses not covered by insurance, extraordinary extracurricular activities, and post-secondary education are common examples. They're generally shared between parents in proportion to their incomes, not split 50/50, and must be reasonable given the family's means and the child's needs.

Can child support be changed later?

Yes. Either parent can apply to vary a support order or agreement if there's been a material change in circumstances, most commonly a significant change in the paying parent's income, but only a new court order or a written agreement that's been filed with the court can actually change the enforceable amount. The FRO itself can't change the amount.

Ontario, Canada

Ontario Child Support: A Parent's Guide

Q: What if we have a shared parenting time arrangement?

If each parent has the child at least 40% of the time over the course of a year, the guidelines don't use a straight table lookup for one parent. Instead, the court considers the table amount each parent would owe the other, the increased costs of running two homes for a shared arrangement, and each parent's overall circumstances.

Q: How is child support enforced in Ontario?

Court-ordered child support is automatically filed with the Family Responsibility Office (FRO), a branch of the Ontario government, unless both parents agree otherwise. The FRO collects payments from the paying parent and forwards them to the receiving parent, and can garnish wages and bank accounts, suspend a driver's licence, intercept tax refunds, and report arrears to credit bureaus for non-payment.

How child support works in Ontario, in plain English: the Federal Child Support Guidelines table lookup, special expenses, and how the Family Responsibility Office enforces support.

Legal sources reviewed: August 11, 2026

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In short: Ontario child support starts with a table lookup under the Federal Child Support Guidelines, based on the paying parent's income and the number of children, which produces a fixed monthly base amount. On top of that, parents typically split additional "special" expenses like child care or extracurricular activities based on their income share. Once an order or filed agreement exists, the Family Responsibility Office handles collection and enforcement automatically.

This is an educational overview written for parents, not lawyers. It isn't legal advice. For anything beyond general understanding, talk to a licensed Ontario family law lawyer.

The Federal Child Support Guidelines in Ontario

Child support amounts in Canada, including Ontario, are set using the Federal Child Support Guidelines (SOR/97-175), a national regulation with province-specific tables. The guidelines work in two layers:

1. Table lookup for the base amount

Each province and territory has its own table, reflecting local tax rates. To find the base monthly amount, you look up the paying parent's annual income and the number of children in the Ontario table. Below roughly $12,000 in annual income, no base amount is payable; tables provide fixed figures up to $150,000 in income, with a formula for calculating amounts above that.

2. Section 7: special or extraordinary expenses

Beyond the table amount, parents typically share specific section 7 expenses: child care costs, health-related expenses not covered by insurance (including premiums), extraordinary extracurricular activities, and post-secondary education costs are the most common categories. These are generally split in proportion to each parent's income, not 50/50, and must meet a reasonableness test given the expense and the family's overall means, courts won't order a parent to fund an expense that's disproportionate to what the family can actually afford.

Shared and split parenting time

If each parent has the child in their care at least 40% of the time over the course of a year, the guidelines don't apply a straight one-directional table lookup. Instead, the court considers the table amount each parent would owe the other, the increased costs of maintaining two homes under a shared-time arrangement, and the overall means and needs of each parent and the child.

Ontario's Child Support Guidelines under the Family Law Act

The Federal Child Support Guidelines apply directly to Divorce Act cases, married parents going through a divorce. For parents who aren't married, or are separated but not divorcing, Ontario has its own Child Support Guidelines, O. Reg. 391/97, made under the provincial Family Law Act. This is a separate statute from the Children's Law Reform Act, which governs decision-making responsibility and parenting time, not support.

In practice, Ontario's provincial guidelines closely mirror the federal ones, using the same tables and the same section 7 approach, so the actual dollar amounts generally come out the same whether your case falls under the federal or provincial guidelines. Which set technically applies depends on whether you're proceeding under the Divorce Act or the Family Law Act, a distinction worth confirming with a lawyer or the court if you're unsure which track your case is on. See the Ontario custody guide for more on when the Divorce Act applies versus Ontario's own statutes.

Applying, varying, and enforcing support

Getting a support order or agreement in place

Parents can agree to a support amount in a separation agreement without going to court, but for it to be enforced by the Family Responsibility Office, it generally needs to be filed with the court. Alternatively, either parent can ask a court to order support as part of a family law proceeding.

Varying support

Either parent can apply to vary an existing order or filed agreement if there's a material change in circumstances, most often a significant change in the paying parent's income, but changes in parenting time or the child's needs can also qualify. Only a new court order, or a written agreement filed with the court, actually changes the legally enforceable amount.

Enforcement through the Family Responsibility Office

Court-ordered child support in Ontario is automatically filed with the Family Responsibility Office (FRO) unless both parents specifically agree otherwise. The FRO acts as the collection intermediary: it collects payments from the paying parent and forwards them to the receiving parent, so parents don't need to exchange money directly. If a parent falls behind, the FRO can:

Garnish wages directly from the paying parent's employer through a Support Deduction Order
Intercept federal income tax refunds and other federal payments
Suspend a driver's licence or, in some cases, a passport
Report arrears to credit bureaus
Seize funds from bank accounts

The FRO cannot change the support amount itself, only a new court order or a properly filed agreement can do that.

Common questions

Does 50/50 parenting time mean no support is owed? Not necessarily. Under the shared-parenting-time rules (40%+ with each parent), the court still looks at each parent's income and the relative table amounts, an income gap between parents can still produce a support obligation even with roughly equal time.

Can support be backdated? Courts can order retroactive support in some circumstances, particularly where a parent's income wasn't accurately disclosed, but generally, applying promptly after a real change in circumstances is the safer path.

What if my co-parent isn't paying? If the order is filed with the FRO, contact the FRO directly to pursue enforcement. If it isn't filed, you can generally file it, or consult a family law lawyer about your options.

Does child support cover post-secondary education? It can, through the section 7 special expenses provisions, but it isn't automatic, it depends on the child's circumstances, the parents' means, and, in many cases, the child's own contribution.

Practical considerations

Because Ontario's table amounts key off the paying parent's income and the section 7 split keys off both parents' proportional incomes, keeping income information current and well-documented matters for both parents, whether you're setting up support for the first time or considering a variation. For the parenting time and decision-making rules that often come up alongside a support conversation, see the Ontario custody guide.

Official Ontario and federal resources

FAQ

Questions, answered

This information is provided for educational purposes only and is not legal advice. Family law varies by individual circumstances and may change over time. Consult a qualified attorney or appropriate official resource for advice about your situation.