Canada Child Support Laws: Guidelines and Calculations

In Canada, child support is calculated under the Federal Child Support Guidelines using the paying parent's gross income and the number of children. Married parents apply under the Divorce Act; unmarried parents apply under provincial legislation that mirrors the federal rules in almost every province.

How to Apply for Child Support in Canada

Applying for child support usually happens as part of a separation agreement or divorce proceeding. You do not always need to go to court. Many parents agree on the amount by simply looking up the payor's income in the Federal Tables and writing that amount into a separation agreement.

If you cannot agree, you must apply to the court. The process depends on whether you are married or unmarried:

• Married Parents: You apply for child support under the federal Divorce Act as part of your divorce application in your province's superior court (e.g., Supreme Court of British Columbia, Court of King's Bench in Alberta).
• Unmarried Parents: You apply under your province's family law legislation in provincial court. While the laws are provincial, the calculation method is almost identical to the federal rules.

Tip: Many provinces now offer online calculation services or administrative recalculation services that can set or update child support without a full court hearing. Check your provincial government's website for "Child Support Recalculation Service."

How is Paternity Established?

Before child support can be ordered, parentage (paternity) must be established. In Canada, federal law defers to provincial laws for the rules on establishing parentage.

Generally, a person is presumed to be a parent if:

• They were married to the birth mother at the time of birth.
• They lived with the birth mother in a relationship of some permanence before the birth.
• They are listed on the birth certificate.

If parentage is disputed, the court can order DNA testing. Once parentage is confirmed, the legal obligation to pay child support begins immediately.

Federal vs. Provincial Guidelines

It can be confusing to know which law applies. Here is the breakdown:

• Federal Guidelines apply if you are getting a divorce, unless both spouses habitually reside in the same designated province.
• Provincial Guidelines apply if you were never married (common-law), if you are separated but not divorcing, and also in a divorce where both spouses habitually reside in a designated province.

The designated provinces: Section 2(1) of the Divorce Act defines the "applicable guidelines" as the laws of the province specified in a designation order where both spouses habitually reside in a province designated under subsection 2(5), and "in any other case, the Federal Child Support Guidelines." Three provinces are currently designated, each by its own order: Quebec (SOR/97-237), New Brunswick (SOR/98-256) and Manitoba (SOR/98-288). Prince Edward Island was designated in 1998, but that order was repealed in 2006. If the spouses habitually reside in different provinces, the Federal Guidelines apply even when one or both of those provinces is designated.

The "Look-Alike" Rule: Outside Quebec, the provincial guidelines are closely modelled on the Federal Guidelines, so the support amount will usually be similar whether or not you were married. Designation is not a licence to diverge freely: subsection 2(5) permits it only where the province's laws establish comprehensive child support guidelines dealing with the matters referred to in section 26.1 of the Divorce Act. Quebec is the substantive exception, using its own calculation model that considers both parents' incomes. If you are divorcing and both of you live in Quebec, New Brunswick or Manitoba, work from that province's guidelines rather than assuming the federal tables apply.

What Does Child Support Cover?

The monthly base amount (the "Table amount") is intended to cover day-to-day living expenses. This includes:

• Food and groceries
• Housing (rent/mortgage, utilities)
• Clothing
• Basic transportation
• Personal care items

The law assumes the recipient parent is also contributing to these costs directly by providing a home and care for the child. The Table amount is the payor's contribution to these basic needs. It does not cover special expenses like daycare or private school tuition (see Section 7 below).

How to Calculate Child Support

Under the Federal Guidelines, the "Table amount" is calculated using just two numbers:

• The Payor's Guideline Income: Section 16 of the Guidelines determines annual income using the sources of income set out under the Total income heading in the T1 General form issued by the Canada Revenue Agency, adjusted in accordance with Schedule III. On the current T1, that heading is Line 15000 (formerly Line 150).
• The Number of Children: The number of children entitled to support.

Step 1: Determine Guideline Income

For most employees, this is straightforward. Start with Total income and apply the Schedule III adjustments. For self-employed individuals or those with complex corporate structures, section 19(1) lets a court impute such amount of income to a spouse as it considers appropriate in the circumstances, using the list of circumstances set out in that section.

Step 2: Check the Tables

Locate the province where the payor lives. Find their income bracket and the column for the number of children. That figure is the monthly base amount, under the presumptive rule in section 3(1).

Child Support Tables (2025/2026)

Justice Canada updated the Federal Child Support Tables to reflect more recent tax rules, and the updated tables came into effect on October 1, 2025.

Which table applies depends on the period you are calculating, not on today's date:

• From October 1, 2025 onward: use the 2025 tables.
• November 22, 2017 to September 30, 2025: use the 2017 tables. These remain the correct tables for that earlier period, which matters when support is being set retroactively or arrears are being calculated.

You can reach the official table look-up here: Federal Child Support Table Look-up.

Note on "Gross-Up": For orders and agreements made on or after May 1, 1997, child support is not deductible for the payor and not taxable to the recipient, so the tables are built on the payor's gross income and are designed to deliver a net benefit to the child. Orders and agreements predating May 1, 1997 can still fall under the older deductible and taxable regime unless they were later changed, so check the date of your order before assuming the current tax treatment applies.

Shared Custody and the 40% Rule

One of the most litigated areas of child support is section 9 of the Guidelines. Readers still search for this as shared custody, but the section itself is keyed to the parenting time each parent exercises, not to a custody label:

"If each spouse exercises not less than 40% of parenting time with a child over the course of a year, the amount of the child support order must be determined by taking into account..."

Source: Federal Child Support Guidelines, SOR/97-175, s. 9

Note the wording: the test looks at each parent's share of parenting time, so it is the threshold being crossed that matters, not which parent is the payor. The section also uses the language of parenting time rather than physical custody, matching the terminology the Divorce Act now uses.

If the 40% threshold is met, the full Table amount is not automatically payable. Instead, section 9 directs the court to consider:

• The Set-Off Amount: Calculate what Parent A would pay Parent B, and what Parent B would pay Parent A (as if each were paying the other). The difference (offset) is the starting point.
• Increased Costs: The increased costs of shared parenting arrangements (e.g., maintaining two full bedrooms).
• Conditions and Means: The financial condition and needs of each parent and the child.

Myth Buster: Reaching 40% parenting time does not automatically mean zero child support. The set-off is a starting point that the other two factors can move, and the higher-earning parent commonly still pays an amount to the lower-earning parent.

Special and Extraordinary Expenses (Section 7)

The basic Table amount covers the basics. "Section 7 expenses" are extra costs that are shared by parents in proportion to their incomes. Section 7(1) lists six heads of expense, and only two of them carry an "extraordinary" test:

1. Special Expenses

• Child care expenses (daycare, after-school care) incurred as a result of the employment, illness, disability, or education or training for employment of the spouse who has the majority of parenting time, under section 7(1)(a).
• The portion of medical and dental insurance premiums attributable to the child, under section 7(1)(b).
• Health-related expenses that exceed insurance reimbursement by at least $100 annually, including orthodontic treatment, professional counselling, and similar costs under section 7(1)(c). Note the wording: the $100 measures the amount left over after insurance pays, not the total bill.
• Expenses for post-secondary education, under section 7(1)(e).

2. Extraordinary Expenses

• Extraordinary expenses for primary or secondary school education, or for any other educational programs that meet the child's particular needs, under section 7(1)(d).
• Extraordinary expenses for extracurricular activities (e.g., competitive hockey, dance, music lessons), under section 7(1)(f).

Post-secondary education is not an "extraordinary" expense. Section 7(1.1) opens with the words "For the purposes of paragraphs (1)(d) and (f)," so the extraordinary threshold, an expense that exceeds what the requesting parent can reasonably cover or that the court otherwise considers extraordinary, applies only to those two paragraphs. Post-secondary education stands on its own as paragraph 7(1)(e), which reads simply "expenses for post-secondary education." A parent claiming tuition does not have to clear the section 7(1.1) test.

Every section 7 expense still has to pass the opening words of section 7(1): the court weighs the necessity of the expense in relation to the child's best interests and its reasonableness in relation to the means of the parents and the child and the family's spending pattern before separation.

How to Share Section 7 Costs:

These costs are usually shared proportionately to income after tax deductions and subsidies are removed. For example, if Parent A earns $70,000 and Parent B earns $30,000, Parent A might pay 70% of the net cost of daycare, and Parent B would pay 30%.

How to Modify Child Support

Child support is not set in stone. It should change whenever there is a "material change in circumstances." Common reasons to modify an order include:

• The payor's income increases or decreases.
• The child creates a new Section 7 expense (e.g., needs braces).
• The parenting arrangement changes (e.g., child moves in with the other parent).
• The child reaches the age of majority.

Annual Financial Disclosure: Section 25(1) of the Guidelines sets the ongoing disclosure duty. A spouse against whom a child support order has been made must provide the listed income documents on the written request of the other spouse or the order assignee, and not more than once a year after the order was made. Section 25(2) extends the same once-a-year mechanism to a spouse whose income falls below the level at which documents would otherwise be required.

The Guidelines do not fix a calendar deadline such as June 30 for that exchange. Individual court orders and separation agreements often do set a specific annual date, so read your own order: the date that binds you is the one written into it, not a national default.

Enforcement: What Happens if You Don't Pay?

The federal government does not directly collect child support. Enforcement runs through a provincial or territorial program, and that program has to ask Ottawa before any federal measure is used.

The program is not called the same thing everywhere. Most provinces and territories run a Maintenance Enforcement Program, but Ontario's is the Family Responsibility Office, British Columbia's is the BC Family Maintenance Agency, and Quebec collects support through Revenu Québec's support-payment collection program. Justice Canada publishes contact details for every provincial and territorial program.

If a payor falls behind (arrears), the enforcement program can request federal action under the Family Orders and Agreements Enforcement Assistance Act (FOAEAA) and the Garnishment, Attachment and Pension Diversion Act (GAPDA).

There is no single national percentage cap. FOAEAA s. 61(a.1) authorizes regulations that prescribe the exempt percentage of garnishable money separately for each federal Act, provision or program, so how much can be taken depends on which payment is being garnished and, for salary, on which province's exemption rules apply. Treat any flat figure you see quoted for all federal money as unreliable, and ask the enforcement program handling your file what applies to your situation.

When Does Child Support End?

The obligation to pay child support does not automatically end at age 18. It continues as long as the child is a "child of the marriage" under the Divorce Act.

• Under Age of Majority: Support is mandatory (unless the child withdraws from parental control).
• Over Age of Majority: Support often continues if the child is unable to withdraw from parental charge due to illness, disability, or, most commonly, pursuing full-time post-secondary education.

For university students, support commonly continues through a first degree, often into the early twenties, though this is a fact-specific decision rather than a fixed cut-off age, and the Table amount may be adjusted if the child lives away from home.

Retroactive Child Support

If a payor's income increased in the past but child support was not updated, the recipient can ask for retroactive support. In D.B.S. v. S.R.G., 2006 SCC 37, the Supreme Court of Canada set the general rule that a retroactive award runs back to the date the recipient gave the payor effective notice, but no more than three years, unless the payor engaged in blameworthy conduct.

Blameworthy conduct is what moves that date. Failing to disclose a material change in circumstances, including an income increase that would have changed the amount payable, is itself blameworthy, and it can push the presumptive date of retroactivity back to the point where circumstances actually changed.

The Supreme Court returned to this framework in Colucci v. Colucci, 2021 SCC 24, where a payor applied under section 17 of the Divorce Act to reduce support retroactively and wipe out arrears. The Court held that a payor who proves a past drop in income is not automatically entitled to a retroactive decrease back to the date of that drop, and it built a mirror image of the D.B.S. approach: support is presumed to be reduced back to the date the payor gave the recipient effective notice, and no further than three years before formal notice of the application. Effective notice from a payor means clear communication of the change together with the documentation needed to substantiate it, not merely raising the subject. The Court also confirmed that this presumption-based approach applies where a recipient seeks a retroactive increase, with the D.B.S. factors guiding any departure from the presumptive date.

Key Child Support Concepts

Try the free Canada Child Support Calculator to estimate the monthly federal table amount for Ontario, British Columbia, and Alberta.

• How the Federal Child Support Tables work
• Shared custody and the 40% rule
• Special and extraordinary expenses (section 7)
• The Quebec child support model
• Retroactive child support

Child Support by Province and Territory

Child support across Canada runs on the Federal Child Support Guidelines, except in Quebec, which uses its own model, and in divorces where both spouses habitually reside in a designated province (Quebec, New Brunswick or Manitoba), where that province's guidelines apply. Each province and territory administers its own enforcement program and recalculation service. Select your jurisdiction for the table amounts, rules, and where to apply.

• Ontario Child Support
• Quebec Child Support
• British Columbia Child Support
• Alberta Child Support
• Manitoba Child Support
• Saskatchewan Child Support
• Nova Scotia Child Support
• New Brunswick Child Support
• Newfoundland and Labrador Child Support
• Prince Edward Island Child Support
• Yukon Child Support
• Northwest Territories Child Support
• Nunavut Child Support

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