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Separation and Divorce: Child Support

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Available formats and options

How can child support be changed?

There are several ways to change existing child support payments.

Make a new agreement

If both parents agree to change child support, they can make an agreement. The agreement must be dated, signed by both parents and a witness.

If the new agreement changes an old agreement that was filed with the court, a Notice of Calculation, or a Notice of Recalculation, then any new agreement should also be filed with the court. If it is not filed with the court, the Family Responsibility Office cannot enforce the new support amount.

If the new agreement changes a final court order, the parents need to ask the court to change their order based on their new agreement.

Use the Ontario government online service

In some cases, parents can use the online Child Support Service (CSS) to change child support. Based on new income information, CSS sends the parents a Notice of Recalculation that tells them how much child support must be paid.

You cannot use the service if you used CSS to decide or change child support less than 6 months ago.

Visit, scroll down the page, and click on the "Set up or update child support" button to change child support using the CSS.

Important: Only one parent needs to ask to change child support online. The other parent does not need to agree. They get a notice in the mail from the Ministry of the Attorney General that says the other parent applied to change child support online and CSS agrees that it can make the change.

The payor parent can disagree if the information the other parent gave was wrong. If they do not respond within 25 days of the notice being sent, CSS might change their support payment without their response.

Get a court order

If the parents cannot agree, or cannot use or do not want to use the online CSS, either parent can ask the court to change child support.

Unless the other parent agrees, the court only makes a change if there has been a significant change. For example, if:

  • the payor parent's income has gone up or down
  • the child has left the parent's house voluntarily
  • the child is now living with the payor parent
  • the child is no longer in daycare or full-time school

A change in the income of the parent getting support is usually not a reason to change the order. This is because that parent's income is not usually taken into account when support is calculated.