Child Support with 50/50 Shared Parenting
It is the most persistent misconception in family law: that equal parenting time means nobody pays child support. It does not. Shared parenting changes how child support is calculated — it does not switch the obligation off.
The 40% threshold
Section 9 of the Child Support Guidelines applies where a parent exercises parenting time of at least 40% over the course of a year. Below that line, the ordinary table amount applies based on the payor's income. At or above it, a different and much more open-ended analysis takes over.
The threshold makes the counting itself worth arguing about, and it is not always obvious. Courts have counted overnights in some cases and hours of actual care in others, and the answer can turn on how holidays, school transitions and mid-week time are treated. A schedule that looks like 50/50 on a calendar does not always clear 40% once it is counted properly — and a schedule that looks lopsided sometimes does.
What section 9 actually requires
Once the threshold is met, three factors must be weighed together:
- The set-off amount. Determine each parent's table amount for the number of children, then subtract the lower from the higher. If Parent A's table amount is $X and Parent B's is $Y, the set-off is the difference — paid by the higher earner.
- The increased costs of the shared arrangement. Two homes cost more than one. Both need bedrooms, clothing, food and equipment, and those duplicated fixed costs do not fall equally on both households.
- The condition, means, needs and other circumstances of each parent and each child. The catch-all — and often the decisive factor.
The Supreme Court has made clear there is no presumption that the set-off is the right answer. It is the starting point for the analysis, not the end of it. A court can order more than the set-off, and frequently does where the income gap is wide.
Why the set-off is often not the final number
The purpose of child support is to keep the children's standard of living reasonably consistent across both homes. Where one parent earns substantially more, a pure set-off can leave the children materially better off in one house than the other — which is precisely the outcome section 9 exists to prevent. The bigger the income disparity, the less likely a straight set-off survives.
Section 7 expenses still get shared
Childcare, medical and dental costs, extracurriculars, post-secondary — special and extraordinary expenses are shared in proportion to income regardless of the parenting schedule. Agreements should say how these get approved before they are incurred, so neither parent is billed for a decision they never agreed to.
Get the schedule right on paper
Because so much turns on the percentage, a vague parenting schedule is an invitation to litigate. The order or separation agreement should be specific enough that a stranger could follow it: regular weeks, holidays, professional development days, summer, travel and communication. Where parents keep colliding on the detail, parenting coordination resolves disputes far faster than a court application.
Note also that a change in schedule is a change in support. If the arrangement drifts — one parent quietly taking more time — the support figure should be revisited rather than left to build up as a grievance. The same applies when one parent wants to relocate.
Frequently asked questions
We agreed neither of us pays. Is that enforceable?
Not necessarily. Child support is the right of the child, not something parents can bargain away between themselves. A court reviewing the agreement can decline to accept a term that leaves a child short, and can order support retroactively.
We have 50/50 time and earn about the same. Does anyone pay?
Often the set-off is small or nil — but section 7 expenses are still shared, and the analysis still has to be done rather than assumed.
Does child support stop at 18?
Not automatically. It can continue for a child still in school or unable to become independent — see when child support continues after 18 in Alberta.
Do I need to disclose my income every year?
Yes, and your agreement should require it from both of you. Annual exchange of tax returns is the simplest way to keep support accurate and avoid retroactive claims.
