Child Support Calculator
This calculator gives a rough monthly estimate of basic (table) child support from the paying parent’s income and the number of children. It approximates the Federal Child Support Guidelines tables with a formula rather than reading the official tables, so its result can differ from the official amount, and it doesn’t handle shared custody, special expenses or Quebec’s separate provincial model. The official amount for your province and income comes from the Department of Justice table lookup. This page is part of our guide to life stages and life events.
A formula approximation of the federal table amounts, not the official tables.
How table amounts work
The Federal Child Support Guidelines set a basic monthly amount from the paying parent’s income, the number of children and the province where the paying parent lives. The tables were updated effective October 1, 2025. The table amount is the starting point in most cases and covers day-to-day needs such as food, clothing and shelter. Quebec uses its own provincial model, which works from both parents’ incomes.
Section 7 special expenses
On top of the table amount, parents share certain special or extraordinary expenses in proportion to their incomes.
| Expense type | Examples |
|---|---|
| Child care | Daycare, after-school care |
| Medical and dental | Orthodontics, therapy, prescriptions not covered by insurance |
| Education | Tutoring, special programs |
| Extracurricular activities | Extraordinary sports, lessons or camps |
| Post-secondary | Tuition, residence |
Example: if the paying parent earns 60% of the parents’ combined income, they pay that share of a $5,000 special expense: $3,000.
Custody arrangements and support
| Arrangement | How support is usually figured |
|---|---|
| One parent has the children most of the time | The other parent pays the table amount |
| Shared parenting (each parent has the children at least 40% of the time) | Each parent’s table amount is calculated and the difference is paid, adjusted for actual costs |
| Split custody (each parent has at least one child) | Each parent’s amount for the child or children with the other parent, offset against each other |
Example (shared parenting offset): if Parent A’s table amount would be $920 a month and Parent B’s $477, Parent A pays the difference, $443 a month, before any adjustment for what each parent spends. The two table amounts here are illustrative, not taken from the official tables.
What counts as income
| Usually included | Details |
|---|---|
| Employment income | Salary, wages, commissions |
| Self-employment income | After reasonable business expenses |
| Pension income | Including CPP and OAS |
| Investment and rental income | Dividends, interest, capital gains, net rent |
| EI benefits | Regular and parental |
A one-time payment may or may not count, depending on whether it recurs, and a new partner’s income generally doesn’t. A court can impute income to a parent who is deliberately unemployed or underemployed, doesn’t disclose income, or keeps income inside a corporation.
When child support ends
| Province | Age of majority | Support until |
|---|---|---|
| Ontario | 18 | 18, or longer if in school |
| BC | 19 | 19, or longer if in school |
| Alberta | 18 | 18, or longer if in school |
| Quebec | 18 | 18, or longer if in school |
| Other provinces | 18 or 19 | Varies |
Support can continue past the age of majority for a child who is still under a parent’s charge, such as one in full-time post-secondary education or one who can’t become self-sufficient because of illness or disability.
Changing child support
Support can be recalculated when the paying parent’s income changes, when parenting time changes, when a child reaches adulthood, or when special expenses change. Parents can agree on the change, use mediation, or apply to court.
Tax treatment and enforcement
Child support paid under current agreements and orders isn’t deductible for the payer or taxable for the recipient, unlike periodic spousal support; how spousal support is taxed is on the spousal support calculator. If support isn’t paid, provincial programs such as Ontario’s Family Responsibility Office, BC’s Family Maintenance Enforcement Program and Alberta’s Maintenance Enforcement Program can garnish wages, seize bank accounts and suspend licences.
Undue hardship
In exceptional cases, a court can change the table amount for undue hardship, such as unusually high debts or support owed to children from another relationship, but only if the household claiming hardship would otherwise have a lower standard of living than the other household.