How to Change a Child Support Order in Ontario

Child support orders are not set in stone. Life changes — incomes rise and fall, children's needs evolve, parenting arrangements shift — and Ontario law provides a process for updating support when those changes are significant enough to warrant it. But the process is not as simple as calling the court and asking for a new number. There are rules about when a change is justified and how to go about making it.

This article explains how to change child support ontario, the different paths available (agreement, online recalculation, or court motion), and what you need to show to succeed.

The Starting Point: Child Support Follows Income

Under the Federal Child Support Guidelines, child support amounts are primarily based on the paying parent's gross annual income and the number of children. The table amount — the base support payable — changes as income changes. This is both the reason support gets outdated quickly and the reason the law provides a clear process for updating it.

When one parent's income changes significantly — up or down — the table amount that applied when the original order was made no longer reflects what the law says should be paid. Either parent can seek to have the order updated.

What Is a "Material Change in Circumstances"?

To change a court order (as opposed to a private agreement), you must generally show there has been a material change in circumstances since the order was made. Ontario courts have interpreted this to mean:

• The change must be significant — not a minor fluctuation but a real shift
• The change must be not have been anticipated when the original order was made
• The change must be such that the original court, had it known about the change, would likely have made a different order

Income changes are the most common trigger. Other examples include:

• A child becomes self-sufficient or changes their primary residence
• The number of children entitled to support changes (for example, an older child finishes post-secondary education)
• A child develops a special need requiring increased expenses
• Parenting time arrangements change substantially (which can affect the support calculation)
• A payor parent loses their job or changes careers

You do not need to show a material change to change a private agreement — both parties can agree to change it at any time in writing. Material change is a threshold for asking a court to change an order over the other party's objection.

Three Paths to Changing Child Support

Path 1: Mutual Agreement

The simplest path. If both parents agree to a new support amount, they can put that agreement in writing and file it with the court as a consent order — or keep it as an updated domestic contract. This requires no motion, no judge, and no argument about material change.

The key: get the agreement in writing. Verbal agreements about child support are practically unenforceable. A written consent order or domestic contract protects both parties and gives clear direction to the Family Responsibility Office (FRO), which enforces support in Ontario.

Path 2: Ontario's Child Support Recalculation Service

Ontario operates an administrative recalculation service that can update child support amounts without going to court, if the order or agreement meets certain criteria. As of writing, the service applies to orders or agreements that:

• Contain a table amount of child support (not special expenses alone)
• Require annual income disclosure
• Are registered with the service

When registered, the service can automatically recalculate support each year based on updated income information that both parties provide. The recalculated amount takes effect without a court appearance. This is designed exactly for cases where support needs regular updating but both parties are cooperating with income disclosure.

Check with the Ontario government's current service information to confirm eligibility requirements, as program details are updated from time to time. This service is underused — many parents who are eligible do not know it exists.

Path 3: Motion to Change in Court

If you cannot agree and the recalculation service does not apply, either parent can bring a motion to change in the Superior Court of Justice or the Ontario Court of Justice. This is a formal court process:

1. The parent seeking the change files a Form 15: Motion to Change along with financial disclosure and the existing order
2. The other parent is served and files a response
3. If disputed, the matter may proceed through case conferences and eventually a hearing
4. A judge decides whether there has been a material change and, if so, what the new amount should be

A motion to change can be brought to increase or decrease support. Both parties have the right to seek the change.

Retroactive support is also possible. If the paying parent had an obligation to disclose an income increase and failed to do so, the court can order support to be paid retroactively to the date of effective notice (the date the other parent first asked about the income change). Courts have developed principles around when retroactive awards are appropriate — it is not automatic, but it is available.

Special Expenses (Section 7 Expenses)

Child support has two components: the table amount (base support) and special or extraordinary expenses (sometimes called section 7 expenses after the relevant guideline provision). These cover costs like:

• Daycare and childcare
• Healthcare not covered by insurance
• Post-secondary education
• Extracurricular activities
• Private school fees (in appropriate circumstances)

Special expenses are shared proportionally to each parent's income. As incomes and expenses change — a child starts university, daycare ends, a sports program is added — the special expense portion can be adjusted. This is often done by agreement but can also be addressed in a motion to change.

Annual Income Disclosure

The Federal Child Support Guidelines require parents to disclose their income annually if asked. Many orders include a clause requiring automatic annual disclosure. If the paying parent has received income increases and has not been updating support accordingly, the recipient parent has grounds to seek a retroactive adjustment.

Keep records. Save your Notices of Assessment from the Canada Revenue Agency each year. If you are the paying parent, proactively sharing your income information annually reduces the risk of a retroactive order later.

Frequently asked questions