CMHC Mortgage Insurance Calculator: Rates, Premiums, and Costs Explained
CMHC Mortgage Insurance: How to Calculate Your Premium Before You Buy
If you're buying with less than 20% down, you'll pay CMHC mortgage default insurance whether you want to or not. It's a federal requirement for any home purchase under $1 million with a down payment below the 20% threshold. The question isn't whether you pay it — it's how much, and how it affects your total purchase cost.
What CMHC Mortgage Insurance Is (and Isn't)
CMHC mortgage default insurance — also provided by private insurers Sagen and Canada Guaranty — protects the lender, not you. If you default and the lender loses money on the foreclosure, the insurer covers the lender's loss. You're paying for protection that benefits your bank, not your household.
That said, it's not all bad. Mortgage default insurance is what allows Canadian lenders to extend 25-year amortizations to buyers with as little as 5% down, at competitive rates. Without it, lenders would price the risk of low-down-payment lending into much higher interest rates — or refuse the loan entirely.
CMHC Premium Rate Table
Your premium is calculated as a percentage of the insured mortgage amount — not the purchase price. The rate depends on your loan-to-value (LTV) ratio:
| Down Payment | LTV Ratio | CMHC Premium Rate |
|---|---|---|
| 5% to 9.99% | 95.01% to 90.01% | 4.00% |
| 10% to 14.99% | 90.00% to 85.01% | 3.10% |
| 15% to 19.99% | 85.00% to 80.01% | 2.80% |
| 20%+ | 80.00% and below | No insurance required |
The premium is added directly to your mortgage principal. You don't pay it upfront at closing (though provincial sales tax on the premium is sometimes due at closing — but not in the Northwest Territories, which has no provincial sales tax equivalent).
How to Calculate Your Specific Cost
The calculation has two steps:
Step 1: Subtract your down payment from the purchase price to get the insured mortgage amount.
Step 2: Multiply the insured mortgage amount by the applicable premium rate.
Example A: $550,000 purchase, 5% down
- Down payment: $27,500
- Insured mortgage: $522,500
- Premium rate: 4.00%
- CMHC premium: $20,900
- Final mortgage balance (premium added): $543,400
Example B: $550,000 purchase, 10% down
- Down payment: $55,000
- Insured mortgage: $495,000
- Premium rate: 3.10%
- CMHC premium: $15,345
- Final mortgage balance: $510,345
Example C: $550,000 purchase, 15% down
- Down payment: $82,500
- Insured mortgage: $467,500
- Premium rate: 2.80%
- CMHC premium: $13,090
- Final mortgage balance: $480,590
The difference between 5% and 10% down on a $550,000 home is $27,500 in additional down payment but $5,555 less in CMHC premium — and $5,555 less added to your principal. Over a 25-year amortization at 5.5%, that $5,555 reduction in principal saves you roughly $5,300 in additional interest. So you're saving more than you think when you increase your down payment from 5% to 10%.
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The Northern Market Reality
In the Northwest Territories, where average prices are $542,075 and rising (up 6.5% in 2025 alone), the CMHC premium carries real weight. On a median-priced home with 5% down, you're adding more than $20,000 to your mortgage before you've written your first mortgage payment.
That premium also affects your amortization ceiling. Insured mortgages are capped at a 25-year amortization. Uninsured mortgages (20%+ down) allow up to 30 years. The longer amortization reduces your monthly payment, giving you more breathing room for northern operating costs that don't exist in southern markets — heating oil (approximately $4,300 per year at current rates), high electricity rates of 25 to 34 cents per kWh, and trucked water and sewer if your property isn't on the municipal pipe system.
Modular Homes: A Special CMHC Issue
Many entry-level properties in Yellowknife are modular or manufactured homes. These properties present a complication in CMHC underwriting that most buyers don't know about until they're already in the process.
CMHC and other default insurers apply age-based amortization limits on manufactured housing. Most major banks assign a maximum 40-year structural life expectancy to modular homes. If you purchase a manufactured home that is already 30 years old, the lender's maximum amortization is compressed to 10 years — dramatically higher monthly payments. Once a manufactured structure exceeds 40 years of age, traditional banks will often refuse to insure or finance the property entirely.
This means a lower-priced $300,000 modular home may come with a 10-year mortgage at higher monthly payments than you'd face on a $450,000 site-built home with a standard 25-year insured mortgage. Always confirm a manufactured home's age and the bank's amortization policy before you make an offer.
What CMHC Insurance Doesn't Cover
A point of confusion for first-time buyers: CMHC mortgage default insurance has nothing to do with home insurance (property and casualty coverage). CMHC protects your lender against your default. Your home insurance policy protects your property against damage, theft, and liability.
Both are required. A lender won't fund a mortgage without both CMHC insurance (if your down payment is below 20%) and an active home insurance policy in place at closing.
In Yellowknife, home insurance carries additional complexity because of heating oil storage tanks. Insurers will refuse to issue a policy on a home with an aging or non-compliant single-walled steel fuel tank. If the tank is uncertified, no insurance — and without insurance, no mortgage. This is a deal-killer that shows up after you've already committed to a purchase if you haven't screened for it during your inspection.
The full process for buying in the Northwest Territories — including how to handle fuel tank compliance, modular home financing, and assembling your down payment with FHSA and Housing NWT program funds — is covered in the Northwest Territories First-Time Home Buyer Guide.
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