# Child Support in Ontario: How the Calculator Works (Explained in Plain Language) If you're separating or divorcing in Ontario and have children, one of your first questions is probably: how much child support will be paid? The good news is that child support in Canada isn't a guessing game. It's calculated using the **Federal Child Support Guidelines**, which include tables showing specific amounts based on income and number of children. There are online calculators that can give you a reasonable estimate in minutes. The less good news is that the calculators don't always tell the whole story. Shared parenting, self-employment income, and special expenses can all complicate things. This guide explains exactly how child support is calculated in Ontario, how to use the calculators, and when you need to look beyond the basic numbers. ## The Basic Formula: Income + Children = Table Amount Child support in Ontario follows a simple core formula. The **paying parent's gross annual income** determines the **table amount** based on the **number of children**. That's it for the basic calculation. You look up the paying parent's income in the table for Ontario, find the row for that income level, and read across to the column for the number of children. The table tells you the monthly amount. For example, if the paying parent earns $60,000 per year and there are two children, the Ontario table shows a specific monthly amount. If they earn $80,000 with one child, the table shows a different amount. The tables are set by federal regulation and are the same across Canada, except that each province has its own table because tax rates differ. In Ontario, you use the Ontario table. ## Where to Find the Calculator The federal government provides an online child support calculator through the Department of Justice Canada website. Search for "child support calculator Canada" or go directly to the Justice Canada website. You can also find calculators on various legal websites and apps. The government calculator is the most authoritative, but others can be useful for quick estimates. To use the calculator, you'll need the paying parent's gross annual income (before taxes), the number of children, the province where the paying parent lives, and basic information about the parenting arrangement. The calculator will show you the **table amount**, which is the basic monthly child support. ## Understanding "Gross Annual Income" The most important number in the child support calculation is the paying parent's **gross annual income**. Getting this number right is crucial. For most employees, gross annual income starts with the "Total income" line on the T1 tax return, which is **line 15000**. This is your income before taxes and deductions. However, the Federal Child Support Guidelines specify that this amount may then be adjusted under **Schedule III** of the Guidelines, which addresses items like certain benefits, spousal support received or paid, and other specific adjustments depending on the circumstances. Gross income typically includes employment income (salary, wages, commissions, bonuses), self-employment income, employment insurance benefits, pension income, investment income (interest, dividends, capital gains), rental income, and other taxable income sources. It does **not** include child tax benefits, GST/HST credits, or social assistance in most cases. ### Self-Employment and Business Income If the paying parent is self-employed or owns a business, determining income is more complicated. Self-employed people can often reduce their taxable income through legitimate business deductions. But some of those deductions (like home office expenses, vehicle expenses, or meals and entertainment) may give a misleading picture of actual money available to pay support. Courts and child support guidelines allow for **adjustments** to self-employment income. The goal is to determine a fair income that reflects the person's actual ability to pay. If self-employment income is an issue in your case, you may need professional help to calculate the appropriate income. This is one area where a lawyer or accountant can add significant value. ### Fluctuating Income Some people have income that varies significantly from year to year. Commission salespeople, seasonal workers, and business owners often fall into this category. When income fluctuates, it may be appropriate to use an **average** of the last three years rather than just the most recent year. This smooths out the ups and downs and gives a more accurate picture of typical income. Courts can also look at the most recent year if there's been a genuine change in circumstances (like a job loss or promotion) that makes the historical average misleading. ## The Table Amount: What It Covers The table amount from the child support calculator covers the children's **basic needs**: food, clothing, housing, and ordinary day-to-day expenses. It does **not** include special or extraordinary expenses like childcare, medical and dental costs not covered by insurance, educational expenses, or extracurricular activities. Those are handled separately under what's called [Section 7 expenses](/glossary#letter-s). The table amount is presumed to be the right amount. In most cases, parents cannot agree to pay less than the table amount without a good reason and, if it's part of a court proceeding, judicial approval. ## When Parenting Time Affects the Calculation The basic table calculation assumes one parent has the children most of the time and the other parent pays support. But what if parents share time more equally? ### Shared Parenting Time (40% or More) If a child spends at least **40% of the time** with each parent over the course of a year, the situation is called [shared parenting time](/glossary#letter-s). The calculation becomes more complex. With shared parenting, both parents' incomes matter, not just the higher earner's. The theory is that both parents have significant child-related expenses because the child lives substantially with each of them. In shared parenting situations, the Federal Child Support Guidelines require courts to consider the table amounts for each parent, the increased costs of shared parenting (maintaining two homes for the child), and the condition, means, needs, and other circumstances of each parent and the child. A common starting point is to calculate what each parent would pay the other under the tables and then set off the difference. However, **this set-off is only a starting point**. Courts have discretion and must consider all the required factors before determining the appropriate amount. Outcomes can vary significantly based on the specific circumstances. The online calculator may give you a rough estimate for shared parenting situations, but it cannot account for all the factors a court would consider. The actual amount often requires negotiation or a court determination. **Important:** The 40% threshold is about time spent with each parent over the full year. As a rough conversion, 40% of 365 days is approximately 146 days, but the legal measure is based on time, which can be argued based on overnights, hours, or the structure of the parenting schedule. If parenting time is close to 40%, the calculation can be contentious. ### Split Custody **Split custody** is different from shared parenting. It applies when there are multiple children and each parent has the majority of parenting time with at least one child. For example, if there are two children and the older child lives primarily with Dad while the younger child lives primarily with Mom, that's split custody. In split custody, each parent calculates what they would owe for the child(ren) living primarily with the other parent. The difference is then paid by the parent who owes more. ## Section 7 Expenses: The Costs Beyond the Table On top of the basic table amount, parents often share **special or extraordinary expenses**, commonly called Section 7 expenses after the section of the guidelines that describes them. Section 7 expenses can include childcare costs required for employment, education, or training, medical and dental expenses not covered by insurance (orthodontics, therapy, prescription medications, etc.), health-related expenses (glasses, hearing aids, mobility devices), educational expenses (tutoring, private school in some cases), post-secondary education costs, and extracurricular activities that are appropriate given the child's needs and the family's means. ### How Section 7 Expenses Are Shared Section 7 expenses are usually shared between parents **in proportion to their incomes**. For example, if one parent earns $80,000 and the other earns $40,000, their combined income is $120,000. The first parent earns 67% of the combined income, and the second earns 33%. So they would typically share Section 7 expenses 67/33. The calculation is: - Parent A's income ÷ combined income = Parent A's share - Parent B's income ÷ combined income = Parent B's share Not every expense automatically qualifies as a Section 7 expense. The expense must be necessary and reasonable given the child's best interests and the parents' financial situations. Parents sometimes disagree about what counts. ### Calculating Total Child Support To get the full picture of child support, you need to add together the **table amount** (paid monthly by the paying parent) plus each parent's **share of Section 7 expenses** (usually paid as they arise, or through monthly estimates). The online calculator typically only shows the table amount. You'll need to calculate Section 7 sharing separately. ## When Income Gets "Imputed" Sometimes a parent's reported income doesn't reflect their actual ability to pay child support. In these cases, income can be [imputed](/glossary#letter-i), meaning the court assigns a higher income than what the parent reports. Common reasons for imputing income include a parent who is voluntarily unemployed or underemployed (working part-time when capable of full-time, or not working at all without good reason), a parent who is hiding income or being paid under the table, a self-employed parent who is using the business to reduce apparent personal income, and a parent who has given up income-earning assets or diverted income to avoid support obligations. If income is imputed, the child support calculation uses the imputed amount, not the actual reported income. This is an area where the calculator can't help you. If you believe the other parent's income should be imputed, you'll need to raise this in negotiations or court. ## Underage of Majority vs Adult Children The child support tables apply to children who are under the **age of majority** (18 in Ontario) or who are over 18 but still dependent because they're in school full-time, have an illness or disability, or have other reasons they can't become independent. Support for adult children (over 18) can be different from support for minor children. The table amounts may still be used as a starting point, but courts have more flexibility to consider the specific circumstances. If you have questions about support for adult children, especially those in post-secondary education, get legal advice. ## Step-by-Step: How to Use the Calculator Here's a practical walkthrough of using the federal child support calculator. **Step 1: Gather the information you need.** You'll need the paying parent's gross annual income (line 15000 of their tax return, potentially with Schedule III adjustments, or your best estimate), the number of children, the province where the paying parent lives, and the parenting arrangement (primary residence with one parent, shared, or split). **Step 2: Go to the calculator.** Visit the Department of Justice Canada website and find the child support lookup tool or calculator. **Step 3: Enter the information.** Select the province (Ontario), enter the annual income, and select the number of children. **Step 4: Review the table amount.** The calculator will show you the monthly table amount. This is the basic child support. **Step 5: Consider adjustments.** Ask yourself: Is the parenting arrangement close to 40/60 or more equal? If so, the simple table amount may not apply, and the calculator cannot fully account for shared parenting factors. Are there Section 7 expenses to add? Should income be different than what you entered (imputed income, Schedule III adjustments, income averaging, etc.)? **Step 6: Calculate Section 7 sharing if applicable.** If there are special expenses, calculate each parent's proportionate share based on income. ## Example Calculations **Important note:** The table amounts in the Federal Child Support Guidelines are updated periodically. The dollar figures used in these examples are for illustration only and may not reflect current amounts. Always check the current tables on the Department of Justice Canada website for accurate figures. ### Example 1: Basic Situation Parent A earns $70,000/year. Parent B earns $35,000/year. Two children live primarily with Parent B. Using the Ontario table for $70,000 income with 2 children, you would find the monthly table amount by looking up the current table. Parent A pays Parent B the table amount each month in basic child support. ### Example 2: With Section 7 Expenses Same situation as above, but the children have $500/month in childcare costs and $100/month in activity fees. Combined income: $70,000 + $35,000 = $105,000 Parent A's share: $70,000 ÷ $105,000 = 67% Parent B's share: $35,000 ÷ $105,000 = 33% Section 7 expenses: $600/month total Parent A's share: $600 × 67% = $402 Parent B's share: $600 × 33% = $198 Total support from Parent A: table amount + $402 (Section 7 share) ### Example 3: Shared Parenting Parent A earns $90,000/year. Parent B earns $50,000/year. One child spends 50% of time with each parent. This is shared parenting (over 40% with each parent). The calculation is more complex. One starting point: Calculate what each would pay the other under the tables, then set off the amounts. However, this is only a starting point. The court must also consider the increased costs of shared parenting and the condition, means, needs, and other circumstances of each parent and the child. For example, if the table amount for Parent A (1 child) is higher than the table amount for Parent B (1 child), the set-off difference might form the basis of an order, but the actual amount could vary based on the specific circumstances and judicial discretion. **Note:** For shared parenting situations, the online calculator cannot fully compute the appropriate amount. Legal advice is often helpful. ## What the Calculator Doesn't Tell You Online calculators are useful starting points, but they have limitations. **They use the table amounts only.** The calculator shows basic support. It doesn't include Section 7 expenses. **They assume straightforward income.** If there's self-employment, fluctuating income, Schedule III adjustments, or imputed income issues, the calculator can't account for these. **Shared parenting calculations require judgment.** For parenting arrangements at or near 40/60, the simple table amount may not apply. The calculator cannot consider all the factors the Guidelines require courts to weigh. **They don't address disputes.** If you and the other parent disagree about income, parenting time, or what expenses count, the calculator can't resolve that. **Child support orders are individualized.** A court can deviate from the guideline amount in certain circumstances. The calculator shows the presumptive amount, not necessarily the final order. **Table amounts change over time.** The calculator uses the tables in effect at the time you use it. Make sure you're using current figures. ## Agreeing to Different Amounts Parents sometimes wonder if they can agree to pay more or less than what the calculator says. **More than the table amount:** Yes, you can agree to pay more. Courts will generally approve this. **Less than the table amount:** This is more complicated. Child support is considered the right of the child, not the parents. Courts are reluctant to approve agreements for less than guideline amounts unless there's a good reason and the children's needs are being met another way. If you're considering agreeing to non-guideline support, get legal advice. An agreement that seems reasonable now might not hold up later. For more on this topic, see our guide on [child support in Canada: how it's calculated and when it changes](/blog/child-support-canada-how-calculated-when-changes). ## When Child Support Changes Child support isn't frozen in time. It can change when there's a **material change in circumstances**, such as a significant change in either parent's income, a change in the parenting arrangement, a child finishing school or becoming independent, or a change in Section 7 expenses. Either parent can ask to vary (change) the child support order when circumstances change. Ontario also has recalculation services that can update support based on updated income information without going to court. For more on this topic, see our guide on [whether child support can be changed](/blog/can-child-support-be-changed-income-parenting). ## Enforcement: What If Support Isn't Paid? In Ontario, the [Family Responsibility Office (FRO)](/blog/child-support-ontario-fro-enforcement) is responsible for collecting and enforcing child support. If support isn't paid, FRO has significant powers including garnishing wages, intercepting tax refunds, suspending driver's licences, and other enforcement measures. ## Child Support vs Spousal Support Child support and [spousal support](/blog/spousal-support-canada-who-pays-how-long) are different things with different rules. **Child support** uses fixed tables. It's based on the paying parent's income and number of children. It's not negotiable in the same way other issues are. It's not taxable to the recipient and not deductible for the payer. **Spousal support** has no fixed tables (though the Spousal Support Advisory Guidelines provide ranges). It depends on many factors. It's more negotiable. And it is taxable to the recipient and deductible for the payer. When calculating spousal support using the SSAG, child support is factored in first. This means the spousal support calculation takes child support obligations into account. ## Getting Help If your situation is straightforward (clear income, one parent has most of the parenting time, no unusual expenses), you may be able to figure out child support yourself using the calculator and guidelines. If your situation involves any of the following, consider getting professional help: self-employment or business income, potential imputed income issues, Schedule III income adjustments, shared or split parenting arrangements, high income (over $150,000, where the tables work differently), significant Section 7 expenses that you disagree about, or any dispute about the appropriate amount. A [family law lawyer](/blog/how-to-choose-a-divorce-lawyer-in-ontario) can help you understand how the guidelines apply to your situation. If cost is a concern, see our guide on [free and low-cost family law help in Ontario](/blog/free-low-cost-family-law-help-ontario). ## Key Takeaways Child support in Ontario is calculated using the **Federal Child Support Guidelines** with Ontario-specific tables. The basic calculation is: paying parent's gross income + number of children = table amount. **Gross annual income** usually starts with line 15000 of the tax return (Total income) and may be adjusted under Schedule III of the Guidelines. Self-employment and fluctuating income may require further adjustments. The **table amount** covers basic expenses. **Section 7 expenses** (childcare, medical, activities) are shared proportionally on top of that. **Shared parenting** (40%+ time with each parent) changes the calculation significantly. Both incomes matter, and courts must consider multiple factors beyond a simple set-off. The calculator cannot fully account for these situations. The 40% threshold is based on time over the year. As a rough conversion, this is approximately 146 days, but the legal measure can be argued based on overnights, hours, or schedule structure. The online calculator shows the basic table amount but doesn't include Section 7 expenses, shared parenting adjustments, or imputed income issues. Table amounts also change over time. You generally **cannot agree to less** than the guideline amount without good reason and judicial approval. You can agree to more. Child support can be **varied** when circumstances change materially, including income changes or parenting arrangement changes. The [Family Responsibility Office](/blog/child-support-ontario-fro-enforcement) enforces child support in Ontario. For complex situations, get legal advice. The calculator is a starting point, not the final answer. ### Disclaimer This article provides general information about how child support is calculated in Ontario. It is not legal advice. Child support calculations can be complex, and the appropriate amount depends on your specific circumstances. For advice about your situation, speak to a family law lawyer.