Secondary-suite refinance calculator (up to 90%)
Since January 15, 2025, Canadian homeowners can get an insured refinance to add housing units: up to 90% of the home's value after the work, up to $2,000,000, amortized up to 30 years, with at most 4 units. On a home worth $1,000,000 when finished, with a $600,000 mortgage and a $250,000 suite, that's up to $850,000 in total.
How much can I borrow to add a secondary suite?
The insured refinance for adding units: up to 90% of the value after the work, since January 15, 2025.
- Toward the suite
- $220,000
- Still to find
- $0
- Insurance premium (estimate)
- Not insured (≤ 80%)
- Conventional refinance instead (80%)
- $320,000
Estimate, not advice. Educational estimate only, not financial, mortgage, tax or legal advice. Lenders, insurers and governments set their own rules and can change them; confirm with a licensed professional before you decide.
Up to $740,000 in total; $220,000 toward the suite.
Assumptions & sources
Assumptions
- SOR/2012-281 s. 6.1: a loan to add housing units may be insured up to 90% of the property's estimated value after completion; the added amount can't exceed the cost; applications received on or after January 15, 2025.
- Premium: estimated with CMHC's standard premium table by loan-to-value; the insurer quotes the actual premium, and provincial sales tax may apply in ON, QC and SK.
- Lenders also apply the stress test and their own policies.
Sources
- Justice Laws — Eligible Mortgage Loan Regulations (SOR/2012-281), s. 6.1: insured loans to add housing units (effective January 15, 2025). Checked .
- Department of Finance Canada — Mortgage insurance rule changes to help homeowners add secondary suites (effective January 15, 2025). Checked .
- Department of Finance Canada — Fall Economic Statement: refinancing up to 90% to build secondary suites (effective December 10, 2024). Checked .
- Justice Laws — Bank Act, s. 418: 80% limit on uninsured residential loans (including refinances) (effective September 1, 2026). Checked .
How this tool works
The cap is the lower of 90% of the "as complete" value and $2,000,000. The new loan is the lower of that cap and your current mortgage plus the cost of the work, because the regulation limits the added amount to the cost. Above 80% the loan is insured and a premium applies; we estimate it with CMHC's standard premium table.
Everything else about qualifying still applies: the stress test, income ratios and the lender's own rules. For an ordinary refinance without the suite, the limit is 80%: see the equity calculator.
Frequently asked questions
Can I refinance to 90% to build a basement suite?
Yes, if the loan is for adding housing units, the home will have at most four units, you or a close relative live in one, and the new unit isn't a short-term rental. The application must have reached the insurer on or after January 15, 2025.
Can I use the 90% refinance for other renovations?
No. The insured refinance is only for adding units; other renovations are limited to the 80% conventional refinance.
Primary sources
- Justice Laws — Eligible Mortgage Loan Regulations (SOR/2012-281), s. 6.1: insured loans to add housing units (effective January 15, 2025). Checked .
- Department of Finance Canada — Mortgage insurance rule changes to help homeowners add secondary suites (effective January 15, 2025). Checked .
- Department of Finance Canada — Fall Economic Statement: refinancing up to 90% to build secondary suites (effective December 10, 2024). Checked .