Parenting calculator · Ontario · 2026
Your parenting-time percentage, counted by overnights.
Set a typical two-week schedule or enter annual overnights, and see each parent's share of parenting time — and whether it crosses the 40 percent line that changes child support. No signup.
Two ways to enter it
Tap out a typical two-week schedule night by night, or enter annual overnights directly — whichever matches how your arrangement is written.
The 40 percent line, made clear
See at a glance whether the schedule crosses into shared parenting, the threshold that changes how child support is calculated.
A path to the support number
When it is shared parenting, a direct link takes you to the child-support calculator to keep going on the numbers.
Cairn's parenting-time percentage calculator is a free tool that works out each parent's share of parenting time — no account, no fee. Parenting time is usually measured by overnights: the number of nights a year the child sleeps at each home. This tool counts those nights, either across a typical two-week schedule or as annual totals, and turns them into a percentage for each parent.
The percentage matters because of one line: 40 percent. Below 40 percent of the overnights, the parent with less time generally pays the full table amount of child support. At 40 percent or more for each parent, the arrangement becomes shared parenting under section 9 of the Federal Child Support Guidelines, and support is worked out as a set-off between the two parents instead. Crossing 60 percent flips who counts as the primary parent. So the same schedule can lead to very different child-support outcomes depending on which side of these lines it lands.
This is an estimate for planning. Courts assess the full-year pattern — holidays, school breaks, and vacation weeks all shift the count — and overnights are the common proxy for parenting time but not the only measure. A schedule sitting near 40 percent is exactly where the numbers get argued, so treat the result as a starting point rather than a final answer.
Your two-week schedule
Tap each night to set who the child stays with. Start with a typical fortnight; the percentage below updates as you go.
0 nights with you · 14 with the other parent
The estimate
Set the nights above to see each parent's share of parenting time and what it means for child support.
What this estimate does not do
- Courts assess the full-year pattern — holidays, school breaks, and vacation blocks shift the percentage away from a typical two-week schedule.
- Overnights are the common proxy for parenting time, but they are not the only measure a court can use.
- The 40 and 60 percent lines are guideposts, not hard switches — a result near a line is exactly where the numbers are argued.
- This is an estimate for planning, not a final figure.
- This is information, not legal advice, and Cairn is not a law firm.
Save to your Cairn dashboard
The full dashboard keeps these numbers and adds the action plan, the Form 13 workspace, a two-budget builder, and the parenting log. About five minutes. No credit card.
Go deeper on parenting time
The parenting-time guide explains how overnights, the 40 percent line, and shared parenting fit together under Ontario's rules.
Reviewed July 1, 2026 · Based on the Federal Child Support Guidelines, s. 9 · Read the parenting-time guide
Common questions
The questions men ask about parenting time and the 40 percent line.
Plain-language answers about how overnights, percentages, and shared parenting actually work for child support in Ontario.
About Cairn
Cairn is an Ontario-built preparation tool for men going through separation. It gives you orientation, document checklists, and the financial picture in plain language — so you can prepare and then work with a legal professional.
Keep your numbers
Save this to a free Cairn account.
- Keep these numbers alongside your full separation plan
- Your specific Ontario next steps, in order
- Free to start — no credit card