Child Support Calculation in Ontario: Tables, Guidelines, and Section 7 Expenses

How Ontario Child Support Works

Child support in Ontario is not discretionary. It is calculated using the Federal Child Support Guidelines (FCSG), which apply to all divorcing parents across Canada. The system is deliberately formulaic: the payor's gross annual income determines a base monthly amount from a lookup table, and the number of children determines which column of that table applies. Ontario courts have almost no discretion to deviate from the table amount for basic support — unlike spousal support, where ranges and judicial judgment play a larger role.

This table-based approach exists because Parliament recognized that child support should be predictable, consistent, and efficient to determine. The days of judges individually assessing each family's budget are over for the basic support component. The tables do the work.

Step 1: Determine the Payor's Income

The starting point is always the payor's gross annual income, typically drawn from line 15000 of their most recent T1 tax return. But the Guidelines definition of "income" goes beyond what the CRA considers taxable income. Several adjustments apply:

• Self-employment income is calculated after deducting reasonable business expenses, but certain deductions that reduce tax liability (like capital cost allowance on non-essential assets) may be added back for support purposes.
• Non-recurring income such as a one-time bonus or capital gain may be averaged over several years rather than counted in full in the year received.
• Imputed income may apply when a parent is voluntarily unemployed or underemployed. If the paying parent quits a $90,000 job to work part-time earning $30,000 without a legitimate reason (illness, retraining, caregiving), the court may impute income at their actual earning capacity.

For salaried employees with stable income, the calculation is straightforward. For business owners, commissioned salespeople, or parents with variable income, determining the correct income figure is often the most contested part of the entire child support process.

Step 2: Look Up the Table Amount

Once income is established, the base child support amount comes directly from the Federal Child Support Guidelines tables for Ontario. The tables are province-specific because they account for different provincial tax rates. You need the Ontario table specifically — not the Alberta or BC table, even though all three fall under the same federal legislation.

The tables are published by the Department of Justice Canada and are freely available online. They list monthly support amounts for incomes from $0 to $150,000 in increments, for one through six or more children. Above $150,000, the table provides a formula (a base amount plus a percentage of each additional dollar above the threshold) rather than a flat lookup.

Use the current Ontario table for the applicable table year, the payor's income, and the number of children. The tables are updated from time to time, and the court will not approve a divorce order where the agreed child support amount deviates from the table without a specific justification on the record.

Section 7: Special and Extraordinary Expenses

The table amount covers basic day-to-day expenses — food, clothing, shelter, routine activities. Section 7 of the Guidelines identifies additional categories of expenses that are shared proportionally between the parents based on their respective incomes:

• Childcare expenses required for the custodial parent to work, attend school, or pursue retraining
• Medical and dental insurance premiums for the child beyond what provincial health coverage provides
• Health-related expenses exceeding $100/year that are not covered by insurance (orthodontics, therapy, prescription medications)
• Extraordinary expenses for primary or secondary education (private school tuition, tutoring for a child with learning disabilities)
• Post-secondary education expenses
• Extraordinary expenses for extracurricular activities (competitive sports, elite arts programs)

The word "extraordinary" matters. Routine soccer registration is typically absorbed into the table amount. A child training at a competitive provincial-level program with $8,000 in annual fees is a section 7 expense. The test is whether the expense is reasonable given the family's pre-separation spending pattern and current means, and whether it is necessary for the child's best interests.

Section 7 expenses are shared in proportion to the parents' incomes. If the custodial parent earns $50,000 and the non-custodial parent earns $100,000, the split is roughly 33/67 — the higher-income parent pays two-thirds of approved section 7 expenses on top of the table amount.

Shared Custody: The 40% Threshold

When a child spends at least 40% of the time with each parent (roughly 146 overnights per year), the standard table lookup no longer applies directly. Instead, section 9 of the Guidelines requires the court to consider three factors:

1. The table amount each parent would pay to the other (a "set-off" calculation)
2. The increased costs of shared custody (maintaining two full households for the child)
3. The conditions, means, needs, and circumstances of each parent and child

In practice, most Ontario courts start with the set-off approach: calculate each parent's table amount as if they were the payor, subtract the lower from the higher, and the parent with the higher table amount pays the difference. But the court retains discretion to adjust this amount based on the actual division of expenses. A parent who carries the child on their health insurance, pays for all extracurriculars, and buys all school supplies may receive a higher amount than a pure set-off would produce.

The 40% threshold matters, but it is not an automatic dollar-for-dollar switch. Below 40%, the ordinary table approach generally applies; at or above 40%, section 9 requires the court to consider both table amounts, the increased costs of shared custody, and the parties' circumstances. The result may be a set-off, but it is not automatically a reduction. This distinction influences parenting schedule negotiations.

What Happens When Income Changes

Child support is not a one-time calculation. Both parents have an ongoing obligation to exchange income information annually (typically by providing tax returns and notices of assessment by June 1 each year). When income changes materially, either parent can bring a motion to vary the existing support order.

Common triggers for variation include job loss, significant promotion or raise, retirement, receipt of an inheritance (which does not directly affect the table amount but may affect imputed income arguments), or a child reaching the age of majority and ceasing to be a dependent.

If you are working through the Ontario divorce filing process and need to understand how child support documentation fits into your Form 8A application and Form 36 Affidavit for Divorce — including the mandatory proof of reasonable financial arrangements under section 11(1)(b) of the Divorce Act — the Ontario Divorce Filing Process Guide covers the complete sequence.

The Section 11(1)(b) Trap for Self-Filers

Here is where child support intersects directly with the filing process: under section 11(1)(b) of the Divorce Act, an Ontario judge has a statutory duty to verify that reasonable child support arrangements exist before signing a divorce order. If the agreed amount deviates from the table amount without explanation, or if the application fails to include income documentation for the paying parent, the judge will reject the divorce package outright.

Self-represented filers commonly stumble here by agreeing to a below-table amount "because that's what works for us" without providing the court with the income evidence and written reasons that justify the deviation. The judge is not being difficult — they are legally required to refuse the order until satisfied that the children's support is adequate.

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