A fill-in worksheet to organize the numbers before you calculate, negotiate, or see a lawyer.
Who this is for: Separating or separated parents in Ontario who want to understand how child support is calculated and gather the figures they'll need. What you'll get: a plain-language walkthrough of the Child Support Guidelines, the "special expenses" rules, the shared-parenting set-off, and worksheet prompts you can complete with real numbers.
⚖️ This is a general guide, not legal advice. It can't account for your specific situation. Use it to get oriented, then confirm the details with a licensed Ontario lawyer.
How child support works in Ontario, in plain language
Child support is the right of the child, not the parents. That means parents can't simply agree to waive it or set it below what the rules require. It's calculated using the Child Support Guidelines — there's a federal version and an Ontario version, and which one applies depends on your circumstances, but the table amounts are the same. Your support generally has two parts:
- The basic table amount — a set monthly figure driven by two things: the paying parent's income and the number of children.
- Section 7 expenses — certain "special or extraordinary" costs that get shared on top of the table amount, split in proportion to each parent's income.
We'll take each in turn, then you'll fill in your own numbers.
The golden rule of this worksheet: we will not quote dollar figures. Support amounts come from the official government tables and change over time. Look up the current numbers yourself (see below) and write them in — anything else risks being wrong.
Part 1 — The basic table amount
The table amount is the foundation. To find it you need just two inputs:
- The paying parent's annual income (usually their gross, line-15000-style total income, with some adjustments).
- The number of children the support is for.
You then look that combination up in the Child Support Guidelines tables for Ontario.
Where to find the real numbers
- Use the federal Child Support Table Look-up tool (Department of Justice Canada) — search "Child Support Table Look-up."
- Confirm the Ontario tables if your situation falls under provincial rules.
- When you find your figure, write down the date you looked it up — these tables are updated periodically.
⚠️ Don't guess income. Self-employment, bonuses, dividends, and a fluctuating salary all complicate "income." If a parent's income isn't a simple T4 number, the figure a lawyer arrives at may differ from a quick estimate.
About imputed income
If a parent is underemployed on purpose, hiding income, or paid in a hard-to-trace way, a court can impute income — meaning it assigns them an income higher than what they report and calculates support on that figure. So "I'll just say I earn very little" is not a strategy. Be ready to show real, documented income for both parents.
Part 2 — Section 7 special or extraordinary expenses
On top of the table amount, certain extra costs can be shared. These are called Section 7 expenses (after the section of the Guidelines that creates them). They're not automatic — they must be reasonable and necessary given the family's means and the child's needs, and the cost is judged against the table amount already being paid.
Common Section 7 categories include:
- Childcare needed because of a parent's work, illness, education, or job search
- Health-related costs above what insurance covers (think significant dental, orthodontics, prescriptions, therapy, vision)
- A portion of medical/dental insurance premiums for the child
- Extraordinary expenses for primary or secondary school or other educational programs
- Post-secondary education costs
- Extraordinary expenses for extracurricular activities
The key word for activities and schooling is extraordinary — ordinary, modest costs are expected to come out of the table amount; it's the bigger-ticket items that get shared.
How Section 7 expenses are split
Unlike the table amount (driven by one parent's income), Section 7 expenses are usually shared in proportion to each parent's income, after accounting for any contribution or subsidy and any tax benefit. So if one parent earns roughly two-thirds of the combined parental income, they'd typically cover roughly two-thirds of an eligible expense.
Tip: keep receipts and give the other parent notice before incurring a big Section 7 expense. Surprise costs are a frequent source of disputes.
Part 3 — Shared parenting and the set-off
Where a child spends at least 40% of the time with each parent (often called shared parenting), the simple table amount may not apply directly. Instead, the starting point is a set-off:
- Figure out the table amount each parent would pay based on their own income.
- Subtract the smaller from the larger.
- The higher-earning parent generally pays the difference.
The set-off is only the starting point — a court can adjust it to account for the actual costs of the shared arrangement and the children's standard of living in each home. The 40% threshold is also genuinely fact-specific (how you count overnights and time matters), so don't assume you've crossed it just because parenting feels roughly equal.
⚠️ Watch out: the difference between "just under 40%" and "just over 40%" can change the math substantially. This is a common pressure point in negotiations — and a good reason to get advice rather than eyeball it.
The worksheet
Fill this in with real, documented numbers. Where you need a table amount, look it up first (Part 1) and write it in.
Step A — The basics
Number of children support is for: ______ Primary arrangement (check one):
- Children live mostly with one parent
- Shared parenting (each parent ≥ 40% of the time)
- Split parenting (each parent has primary care of at least one child)
Step B — Incomes
Parent A annual income (documented): $__________ Parent B annual income (documented): $__________ Combined parental income: $__________
Parent A's share of combined income: ______% Parent B's share of combined income: ______% (Each parent's income ÷ combined income. You'll use these percentages for Section 7.)
Is there any reason income might be imputed for either parent (under-employment, undisclosed income, self-employment)? ____________________________
Step C — The table amount
Paying parent: ______ Their income used for the table: $__________ Number of children: ______ Table amount looked up: $__________ per month Date and source of look-up: ____________________________
If shared parenting, do the set-off: Table amount Parent A would pay: $__________ Table amount Parent B would pay: $__________ Set-off (larger minus smaller): $__________ paid by ______
Step D — Section 7 expenses
| Expense | Annual cost | Net cost after subsidy/tax | A's share (___%) | B's share (___%) |
|---|---|---|---|---|
| Childcare | $______ | $______ | $______ | $______ |
| Health/dental (above insurance) | $______ | $______ | $______ | $______ |
| Extracurriculars (extraordinary) | $______ | $______ | $______ | $______ |
| Education | $______ | $______ | $______ | $______ |
| Other: __________ | $______ | $______ | $______ | $______ |
| Totals | $______ | $______ | $______ | $______ |
Step E — Putting it together
Monthly table / set-off amount: $__________ Plus monthly share of Section 7 (annual total ÷ 12): $__________ Estimated total monthly child support: $__________
This is an estimate to organize your thinking, not a final number. A lawyer will pressure-test the income figures, confirm which Guidelines apply, and check whether any special circumstances change the result.
Mini-FAQ
Does child support stop automatically at 18? Not necessarily. Support can continue for an adult child who is still dependent — for example, because they're in full-time post-secondary education or have a disability. The arrangement changes, but it doesn't always end at 18.
Can we just agree on a number and skip the tables? You can agree, but a court can override an agreement that gives a child less than the Guidelines support without good reason. Because support belongs to the child, parents can't bargain it away.
What if the paying parent's income goes up or down later? Child support is generally meant to track income over time. A material change in income is a basis to recalculate — keep exchanging income information annually.
How Treadstone Law can help
Treadstone Law helps Ontario parents calculate child support correctly the first time — pinning down income, sorting out Section 7 expenses, and handling the shared-parenting set-off — and puts the result into an agreement that holds up. We work on flat fees where we can, and you can handle everything online or by phone.
- Start online any time at treadstonelaw.ca/start-file
- See flat-fee options at treadstonelaw.ca/pricing
- Learn more about our family law services at treadstonelaw.ca/family
- Have a quick question? Call 1-844-900-1070
This is not legal advice
This guide is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.