If you are separating or adjusting a parenting plan, it is normal to ask what child support will look like on a month-to-month basis. In Ontario, the starting point is not a guess or a “typical” number. It is a structured calculation under child support guidelines that focuses on the paying parent’s income, parenting time, and certain child-related expenses.
This guide explains how child support for one kid in Ontario is usually calculated, when it can change, and what parents often miss when they try to estimate it on their own.
Child Support for One Kid in Ontario: Start With the Table Amount
For many families, the base amount of support is the “table amount.” The table amount is tied to the paying parent’s gross annual income and the province where the paying parent lives, and it is meant to cover the everyday costs of raising a child. In Ontario, the provincial Child Support Guidelines rely on the Federal Child Support Tables (with Ontario-specific application details).
A quick way to estimate the table amount is the federal online Child Support Table Look-up tool. Its calculator is designed to help you compute the monthly table support based on income, number of children, and province. The updated tables took effect on October 1, 2025.
Keep in mind: Table amounts are a starting point, not always the final answer, especially when parenting time is shared or when there are significant extra expenses.
What Income Number Is Used to Calculate Child Support?
Most calculations begin with the paying parent’s gross annual income, using reliable income documentation. When a court is asked to make a child support order, the guidelines set out financial disclosure expectations (including income tax returns and related records).
In real life, disputes often happen because income is not straightforward. Examples include:
- variable bonuses or commissions
- seasonal work or layoffs
- self-employment or cash-heavy businesses
- corporate income and shareholder benefits
If income is contested, the guidelines include tools the court can use to determine income and, in some cases, to impute income when the reported number does not reflect what a person should be earning.
Does Parenting Time Change the Amount for One Child?
Yes, and this is where many “back of the napkin” estimates fall apart.
If one parent has the child most of the time, the table amount paid by the other parent is often the starting point.
If parenting time is shared, support can change. The guidelines address shared parenting and allow the court to consider the table amounts for each parent, the increased costs of shared parenting, and each parent’s means and needs.
A practical way to think about it is that shared parenting does not automatically mean “no support.” In many shared arrangements, one parent still pays support because incomes are different, and the child’s standard of living should not swing wildly between homes.
What Child Support Covers and What Extra Means
Table child support is meant to cover ordinary day-to-day costs. Parents will sometimes describe it as financial support for one child that helps with things like food, clothing, basic school needs, and routine activities.
On top of that, some expenses may be treated separately as “special or extraordinary” expenses (often called section 7 expenses). These can include child care needed for work or school, certain medical and dental costs, and some educational or extracurricular expenses.
The guidelines’ approach is that eligible extra expenses are usually shared in proportion to the parents’ incomes, rather than being fully absorbed by the parent who pays table support.
When the Table Amount Can Be Different From the Child Support Tables
Even when you start with the table amount, the final number can shift in specific situations that the guidelines recognize, such as:
- Undue hardship claims: In limited cases, a parent can argue that applying the table amount would cause undue hardship, and the guidelines set out a test for this.
- Very high incomes: The guidelines include a different approach once income reaches higher ranges, and courts may look beyond a simple table figure.
- Older children and changing needs: Support can continue past 18 in some circumstances, depending on the child’s situation. (More on that below.)
This is also why two families with the same income can end up with different outcomes. Parenting schedules, benefit coverage, child care costs, and school plans can all matter.
How Long Does Child Support Last in Ontario?
There is no one-sentence answer that fits every family, but there are clear legal concepts behind it.
Under federal law, courts can make child support orders for “children of the marriage,” and the Divorce Act sets out the framework for child support orders and the principle that parents share a joint financial obligation according to their abilities.
In practice, support commonly continues to age 18, but it can extend beyond that when a child remains dependent, such as while pursuing post-secondary education or living with a disability. The details can depend on the facts, the child’s needs, and the parents’ finances.
What if the paying parent is self-employed or the income is hard to verify?
Self-employment can raise real issues, because income for child support purposes is not always the same as what shows up as personal taxable income after deductions.
The guidelines include rules that help courts look at the true financial picture, including situations where someone is intentionally under-employed or where reported income does not fairly reflect available resources.
If you are trying to estimate child support for one kid in Ontario and the paying parent’s income is complicated, it is often worth treating your estimate as a rough range until financial disclosure is complete.
What if circumstances change after the amount of child support is set?
The agreed money is not always “set and forget.” Child support amounts can be adjusted when there is a meaningful change, like:
- a major income increase or job loss
- a change to the parenting schedule
- new child care or medical costs
- the child is moving for school
Ontario’s guidelines apply to support orders and variations, and the federal framework supports updates when the facts change.
If you are dealing with an adjustment, it helps to stay focused on proof: updated income documents, a clear parenting calendar, and receipts for expenses. That evidence usually matters more than arguments about what feels fair.
Where Family Law Can Help
Many parents can estimate table support with online tools, but disputes are rarely just about the table. Parenting time, income disclosure, section 7 expenses, and settlement terms can all affect the outcome.
If you want legal guidance specific to your situation, work with a family lawyer who specializes in guidance on child support matters, including advice on calculation issues and support disputes.
Getting to a Reliable Number for Child Support Payments
The most accurate way to estimate support is to start with the table amount, confirm the correct income figure, and then check whether parenting time or special expenses change the result. Online tools can give a fast baseline, but the details matter, especially with shared parenting, self-employment income, or major child-related costs.
If you are trying to plan a realistic budget or negotiate a fair arrangement, treating child support as financial support for one child with clear rules can make the process feel less personal and more manageable.