What is the difference between the Federal and Ontario Child Support Guidelines?

Two sets of Child Support Guidelines apply in Ontario depending on the legal relationship between the parents. The Federal Child Support Guidelines apply when parents were married and are divorcing under the Divorce Act. The Ontario Child Support Guidelines apply when parents were in a common-law relationship or were never together, and the application is made under the Family Law Act.

In practice, the two sets of guidelines are almost identical. They use the same income tables, the same definition of income, the same approach to special expenses, and the same rules for shared, split, and sole-custody arrangements. The Ontario tables were deliberately designed to mirror the federal tables to ensure consistent outcomes regardless of the parents' legal status.

The key practical difference is jurisdictional: which court and which legislation govern the proceeding. Married parents divorcing will go through a process governed by the Divorce Act, while unmarried parents will proceed under the Family Law Act and provincial court rules. The table amounts themselves are the same, so children of married and unmarried parents receive the equivalent protection. When drafting a separation agreement, it is good practice to specify which guidelines apply and to ensure the agreement references the applicable legislation. A lawyer can help you identify the right framework for your situation.