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MayHow Is Child Support Calculated in Ontario? A 2026 Guide
Child support in Ontario is one of the few areas of family law where the right answer is, most of the time, mechanical. The Federal Child Support Guidelines set out tables based on the paying parent's income, the number of children, and the province where they live. Plug in the numbers and out comes the table amount. The disputes are rarely about the tables themselves. They are about the income figure that goes into them, the special expenses that come on top, the way shared parenting affects everything, and the situations where the tables do not apply.
This guide walks through how child support actually gets calculated in Ontario in 2026, what is mandatory and what is discretionary, and what trips parents up most often.
The two statutes that matter
Child support in Ontario can come from one of two places, depending on the parents' situation:
- The federal Divorce Act governs child support claims between divorcing or divorced parents. The Federal Child Support Guidelines are made under the Divorce Act.
- The Ontario Family Law Act governs child support claims between unmarried parents and between separated (but not divorcing) married parents. Ontario has adopted the Federal Child Support Guidelines under O. Reg 391/97, so the table amounts are the same regardless of which statute applies.
The choice of statute affects court jurisdiction and a few procedural details, but the substantive math is the same.
The table amount: the starting point for almost every case
The Federal Child Support Guidelines include tables for every province and territory. The Ontario table is what applies to Ontario-resident payors. To find the table amount, you need three pieces of information: the payor's annual income, the number of children, and the province (Ontario).
Take those three numbers, look them up on the federal child support tables (a free online lookup tool), and you have the monthly child support amount. For most "table cases" — where one parent has the children primarily and the other parent pays support — the table amount is presumptively payable.
The Government of Canada also publishes a Child Support Online Lookup tool that does the math for you. It is the same tool family lawyers use as a starting point.
The income number is where most of the fight happens
The simplest cases involve a salaried employee with a single T4. The income for child support purposes is essentially the employment income on line 15000 of the tax return, sometimes adjusted for specific items under section 16 and Schedule III of the Guidelines. There is little to argue about.
The harder cases involve self-employed payors, business owners, or payors with significant non-employment income. In those cases:
- Personal use of corporate assets — vehicles, travel, club memberships paid through the business — is added back.
- Retained earnings in a corporation can be attributed to the payor under section 18 of the Guidelines, where the corporation is closely held and the retained earnings represent the payor's available means.
- Imputed income can be assigned under section 19 where the payor is intentionally underemployed, has unreasonable expenses, or fails to provide the required disclosure.
- Capital gains, dividends, and partnership income are included with adjustments.
- Foreign income is included.
Section 21 of the Guidelines requires the payor to provide three years of tax returns, three years of T4s/T4As/financial statements, and information about any corporation in which they hold an interest. This disclosure is mandatory, not optional, and a payor who refuses to disclose can be ordered to pay an imputed income amount well above their actual income.
For a self-employed payor with a corporation, getting the income number right typically requires the family lawyer to work with an accountant — and sometimes to retain a forensic accountant if the disclosure is incomplete.
Section 7: special and extraordinary expenses
The table amount covers everyday costs of raising the child — food, housing, clothing, transportation, basic activities. It does not cover everything. Section 7 of the Guidelines lists "special and extraordinary expenses" that can be added on top of the table amount and shared between the parents in proportion to their incomes:
- Childcare costs incurred because of the parent's employment, illness, or education.
- The premium portion of medical and dental insurance attributable to the child.
- Health-related expenses exceeding insurance reimbursement (orthodontics, prescription drugs, glasses, therapy) above a threshold.
- Extraordinary primary or secondary school expenses, including private school where appropriate.
- Post-secondary education expenses.
- Extraordinary expenses for extracurricular activities — competitive sports, music lessons, summer camps — where the cost is significantly more than what most families would pay.
The two-step test for section 7 expenses is reasonableness in light of the parents' means and the family's pre-separation pattern of expenses, plus necessity having regard to the child's best interests. Not every cost the receiving parent wants to share gets included.
Net of any tax credits or deductions, the section 7 amount is divided in proportion to the parents' incomes, not equally.
Shared parenting changes everything
Where each parent has the children at least forty percent of the time, section 9 of the Guidelines applies and the calculation is no longer the simple table lookup. Section 9 says the court considers three factors:
1. The amount the Guidelines would direct each parent to pay if they were the receiving parent — usually expressed as the "set-off" of the two table amounts. 2. The increased costs of shared parenting arrangements. 3. The conditions, means, needs, and other circumstances of each parent and child.
In practice, courts often start with the set-off of the two table amounts as a baseline and then adjust upward or downward for the second and third factors. Section 9 cases are not formulaic; the case law is extensive and often the result varies significantly depending on the facts. Contino v. Leonelli-Contino (Supreme Court of Canada, 2005) remains the leading case on how section 9 is applied.
Split custody, undue hardship, high incomes
A few additional situations follow their own rules:
- Split custody (one or more children primarily with each parent) is dealt with under section 8 — the table amounts are calculated for each parent and the difference is paid by the higher-table parent.
- Undue hardship under section 10 lets a payor (or recipient) argue for a different amount than the table where applying the table would cause undue hardship and the household standard of living is not higher than the other household's. This is a high bar and is rarely successful.
- High-income payors above a Guidelines threshold are subject to section 4 — the table is presumptive up to the threshold, and the court has discretion above it. Most high-income cases settle at the table amount, but the discretion exists.
Ongoing obligations: review and disclosure
A child support order is not "set and forget." The payor's obligation to disclose updated income annually under section 25 of the Guidelines applies if the payee asks for it (and continues automatically by court order in many cases). When income changes meaningfully, the support amount usually changes too — either by agreement using a recalculation service, or by a motion to vary.
Failing to update support when income rises is one of the most common ways arrears build up. Failing to update when income falls means a payor is paying more than they should be. Both are fixable; both require the disclosure to actually happen.
How a Brampton family lawyer fits in
The mechanics of child support in Ontario are not, in most cases, where a family lawyer adds the most value. Where a lawyer earns their keep is on the income figure for self-employed payors, the section 7 issues, the section 9 shared-parenting analysis, and structuring an agreement that anticipates future income changes. If you are dealing with child support in Brampton or the GTA, book a free consultation with GS Arora Law.
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This article is general legal information about Ontario and Canadian family law in 2026 and is not legal advice. For advice on your specific situation, speak with a lawyer.
GS Arora, Lawyer & Notary Public. Brampton, Ontario.