Legal Review
This guide was reviewed by Deepa Tailor, Senior Family Lawyer, to ensure compliance with Ontario family law.
Why hitting the 40% parenting time threshold changes everything. Understanding Shared Custody, the ‘Set-Off’ calculation, and how to structure a schedule that works.
Legal Review: This custody guide was reviewed by Deepa Tailor, Senior Family Lawyer , to ensure compliance with Section 9 of the Federal Child Support Guidelines (2026).
In Ontario family law, the 40% mark is the dividing line between ‘Sole Custody’ and ‘Shared Custody’ for financial purposes.
The Payor pays the Full Table Amount based on their income.
The Payor enters a ‘Shared Custody’ regime (Section 9). Support is determined under section 9, which considers both parents’ table amounts (a set-off of those amounts is only a starting point), the increased costs of shared parenting, and each household’s condition, means and needs. The result is often, but not always, lower.
To qualify for the reduction, you need 146 nights per year (40% of 365).
Every other weekend (Friday to Sunday) is only about 14% time. Even adding a Wednesday dinner visit brings you to only 18%. You pay Full Table Support.
Every other weekend (Thursday to Monday morning) gets you closer to 28%. Still not enough for the reduction.
Example: 4 nights with Dad, 3 nights with Mom (or vice versa). Or a Week-On/Week-Off schedule with one mid-week visit. This hits the 40% threshold.
The ‘2-2-3’ or ‘Week-On/Week-Off’ schedule implies 50% time (182 nights). This meets the 40% threshold, so support is determined under section 9.
Dad earns: $100,000
Mom earns: $60,000
Dad has the kids: 39% of the time
Dad pays Full Table Amount (~$1,500/mo)
Dad hits: 40% time
Result: Section 9 Calculation
Dad owes: ~$1,500
Dad pays difference: ~$600/mo
(Saving $900/mo!)
Parent A has Mon-Tue-Wed-Thu. Parent B has Fri-Sat-Sun. Then swap the following week. Over two weeks this averages 50% / 50%.
Parent B has alternate weekends (Fri-Mon) PLUS every Wednesday overnight. That is 5 of every 14 nights (about 130 nights a year, roughly 36%), which is below the 146-night threshold.
The simplest way to achieve 50/50. Requires older children and parents who live close to the school.
Be careful. Fighting for one extra night just to save money is obvious to judges. The schedule must be in the Child’s Best Interest, not the wallet’s best interest.
Understanding how child support is calculated in Ontario
Professional parenting plan drafting and templates
How to modify existing child support orders
Senior Family Lawyer
Deepa Tailor is the founder of Tailor Law. She helps parents negotiate shared parenting schedules that maximize time with children while ensuring financial obligations are fair and legally compliant.
Understanding the 40% threshold and shared custody calculations requires expert guidance. Let us help you structure a parenting schedule that works for your family.
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