When can child support be modified in Canada?
Child support can be changed when there is a material change in circumstances — most commonly a significant change in the payor's income (typically 10%+ change), a change in the number of children receiving support, or a change in the child's living arrangements. Either parent can apply for a variation.
How far back can retroactive child support go in Canada?
Under the Supreme Court's Colucci v. Colucci (2021) ruling, courts can order retroactive support back to the date a formal request was made or when the payor had notice that a change was needed. In practice, courts rarely go back more than 3 years unless there was blameworthy conduct. Courts balance the recipient's legitimate claim against prejudice to the payor.
Do I need to go to court to modify child support?
Not necessarily. If both parents agree to the new amount, you can file a consent order or written agreement (which should be registered with the court). If you disagree, you must apply to court for a variation order. Many provinces offer family dispute resolution services as a first step before court proceedings.