Overview
- Without children: duration is 0.5 to 1.0 years of support per year of cohabitation. With children: the minimum runs until the youngest starts school; the maximum runs until the youngest finishes high school.
- “Indefinite” does not mean permanent — it means no fixed end date. It is triggered after 20+ years of cohabitation or under the Rule of 65 (age + years ≥ 65, with at least 5 years together).
- Support orders can be changed through a review (no material change needed) or a variation (requires proving a material change in circumstances).
On this page
Duration is often more contested than the monthly amount. Payors want to know when the obligation ends; recipients want to know how long they can rely on it. The SSAG provide duration ranges alongside amount ranges — but the rules differ significantly depending on whether there are dependent children.
This article explains both duration frameworks, the indefinite support triggers, worked examples showing how duration is calculated, and the mechanisms for changing a support order after it is made.
Without-Child Duration
When there are no dependent children, duration scales linearly with the length of the relationship:
WITHOUT-CHILD DURATION FORMULA
Minimum: 0.5 years of support per year of cohabitation
Maximum: 1.0 years of support per year of cohabitation
For a 10-year relationship with no children, the duration range would be 5 to 10 years. For a 6-year relationship, the range would be 3 to 6 years. The formula is deliberately simple — the complexity in the without-child formula is in the amount calculation (1.5-2% of income difference per year), not the duration.
With-Child Duration
When there are dependent children, duration is anchored to children's school milestones rather than just marriage length. The formula uses the longer of two tests at each end of the range:
Minimum Duration
The longer of: half the length of cohabitation, OR the time until the youngest child starts full-time school (September of the year they turn 6)
Maximum Duration
The longer of: the full length of cohabitation, OR the time until the youngest child finishes high school (June of the year they turn 18)
This means parents with very young children can face longer minimum durations than the marriage length alone would suggest. For example, a 4-year relationship where the youngest child is 1 year old at separation: the marriage-based minimum would be 2 years (half of 4), but the school-milestone minimum is 5 years (until the child turns 6). The school milestone wins because it is longer.
WORKED EXAMPLE
Scenario: 8-year relationship, youngest child age 3 at separation
Minimum: longer of 4 years (half of 8) or 3 years (until child starts school at 6) = 4 years
Maximum: longer of 8 years (full marriage) or 15 years (until child finishes high school at 18) = 15 years
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try it freeIndefinite Support
"Indefinite" is one of the most misunderstood terms in family law. It does not mean permanent or lifelong. It means that no fixed end date is set at the outset — the order remains in effect until it is varied or terminated by a court. Indefinite support is still subject to review and variation.
Both SSAG formulas share two indefinite triggers:
INDEFINITE DOES NOT MEAN FOREVER
An indefinite support order can still be varied or terminated if circumstances change materially — for example, if the recipient becomes self-sufficient, remarries, or the payor retires. The order simply does not have a built-in expiry date.
Review vs Variation
Once a support order is made, there are two mechanisms to change it:
The distinction matters. A review order is more flexible — it allows reassessment without the burden of proving a material change. A variation requires the applicant to clear a higher threshold. Lawyers often negotiate for review terms in consent orders to preserve flexibility without the adversarial burden of a formal variation application.
Sources & Further Reading (4)
Spousal Support Advisory Guidelines: Final Version (July 2008), Rogerson & Thompson — Chapter 7 (without-child duration), Chapter 8 (with-child duration)
Spousal Support Advisory Guidelines: The Revised User's Guide (April 2016)
Divorce Act, RSC 1985, c 3 (2nd Supp), s. 15.2 (spousal support orders), s. 17 (variation orders)
SSAG FAQs (2022/2023), Rollie Thompson
This article is for general information only and does not constitute legal, financial, or tax advice. Family law matters vary by jurisdiction and individual circumstances. Consult a qualified family law lawyer or tax professional licensed in your province for advice specific to your situation.
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