Child support is calculated based on Federal or sometimes provincial Child Support Guidelines ("CSG"). In general, monthly "Table" child support is to cover day-to-day expenses, including food, clothing, and school supplies and is based on the gross annual income of the payor parent and the number of children involved. There are exceptions to the above where the parenting schedule for the children is "shared" or "split" between the parents.

The determination of a payor's income is very important and can be challenging where the payor is self-employed, has variable income, lives in a different jurisdiction, or where income is taxed in different ways than a salaried employee.