Mortgage Interest Rates Explained

Borrowers often hear 'the mortgage rate' as if there is only one number. In practice, several rate concepts can appear in the same transaction, and confusing them can lead to bad comparisons.

The contract rate is the rate that actually governs interest under the mortgage contract. A qualifying rate can be higher and is used to test whether the borrower can support the mortgage. A lender may also publish a posted rate, negotiate a discounted rate, price a variable mortgage as a spread to prime, and disclose an annual percentage rate (APR) where applicable.

The first discipline is therefore to ask: What rate is this number, what does it control, and for what period is it valid?

The Bank of Canada sets its policy interest rate as part of monetary policy. Financial institutions set and publish their own prime rates. Prime rates often move when the policy rate changes, but the lender's prime is still the lender's reference rate—not the Bank of Canada policy rate itself.

A variable mortgage can then be priced relative to that reference rate. If the contract says prime − 0.50%, the spread is minus 0.50 percentage points. If the lender's prime changes, the mortgage rate generally changes according to the contract even though the spread may remain the same.

That distinction matters when comparing two variable offers. A borrower should compare the actual pricing formula and product mechanics, not merely the number displayed on the quote today.

Lenders can publish posted rates and offer approved borrowers a lower negotiated or discounted rate. The contract rate is the rate actually written into the mortgage. Those terms should not be treated as marketing trivia because some lenders' prepayment-charge methodologies can use posted or comparison rates as inputs.

This is why two five-year fixed mortgages at apparently similar contract rates can have very different early-exit economics. The Mortgage Penalty Calculator can help with planning, but the lender's own payout statement or current penalty calculation is the figure to rely on before a real transaction.

A good rate comparison therefore asks not only 'what rate do I get?' but also 'how is the lender's break cost determined if my plan changes?'

On a large balance, a difference that looks small in percentage points can materially change cash flow. For illustration, on a $600,000 mortgage amortized over 25 years, a 4.50% nominal rate produces a monthly payment of roughly $3,321, while 5.00% produces roughly $3,490 using standard Canadian mortgage compounding assumptions. That is about $169 more per month before considering any other product differences.

But payment is only one output. A lower rate can also change interest paid and balance remaining at the end of the term. Use the Mortgage Payment Calculator and Amortization Schedule Generator to compare the complete balance path.

The illustration is not a rate quote and does not include fees, insurance premiums or other transaction costs.

Mortgage qualification can use a higher rate than the contract rate. For uninsured mortgages subject to OSFI's current minimum qualifying rate at federally regulated lenders, the prescribed rate is the greater of the mortgage contract rate plus 2 percentage points or 5.25%, subject to the current scope and straight-switch treatment.

That means a borrower can be offered a contract rate that produces an affordable actual payment but still be required to demonstrate capacity at a higher qualifying payment. Qualification is therefore a separate question from pricing.

Use Mortgage Stress Test Math for the calculation and Mortgage Qualification for the broader approval framework.

For federally regulated financial institutions, cost-of-borrowing disclosure can show an annual percentage rate (APR) in addition to the annual interest rate. FCAC's mortgage information-box example describes APR as an annualized measure that includes applicable fees such as certain service, origination or administrative charges when they apply.

APR can therefore help expose a difference between the advertised interest rate and the broader disclosed borrowing cost. It still does not capture every possible financial consequence of the mortgage—for example, a future prepayment charge depends on what actually happens later.

When comparing offers, read the disclosure document rather than assuming the lowest nominal interest rate automatically has the lowest overall cost.

During preapproval, a lender may be able to lock in an interest rate for a period of time. FCAC notes that lender preapproval processes may allow a rate to be held for roughly 60 to 130 days depending on the lender.

A rate hold protects a pricing opportunity subject to the lender's rules; it does not turn a preapproval into unconditional financing. The eventual property, borrower documents, credit, down payment, appraisal and other conditions can still matter to final approval.

If you are buying, connect the rate hold to Mortgage Commitment and Conditions and Condition of Financing.

A fixed rate remains fixed for the term. A variable rate can move during the term. Variable mortgages can also differ in how the payment reacts: some adjust the payment as rates move, while some keep the scheduled payment fixed for a period and change how much goes to interest and principal.

A hybrid or combination mortgage divides the borrowing into fixed and variable portions. FCAC notes that the portions can have different terms, which can make the structure more complicated to transfer later.

This page explains the pricing vocabulary. Use Fixed vs Variable Mortgage for the actual rate-risk decision.

The interest rate attached to a term does not automatically continue for the entire amortization. At maturity, the remaining balance normally needs a new term, and the borrower can face a new rate environment.

FCAC specifically encourages borrowers to shop and negotiate at renewal rather than assuming the first renewal offer is the best available rate. A discounted rate may be negotiable with the current lender, and switching may be worth examining where another lender offers a better overall structure.

The correct comparison is not just renewal rate versus renewal rate. It can include qualification, switching costs, remaining amortization, prepayment features and whether the borrower actually needs to refinance. Use the Mortgage Renewal Centre for that decision.

The headline rate matters, but a mortgage is a contract that may survive for years. A slightly lower rate can lose its advantage if the mortgage has a materially higher break cost, unsuitable prepayment rules, poor portability for an expected move, fees that are not captured in the simple rate comparison, or a structure that does not fit the borrower's likely holding period.

A Toronto funded file illustrates the whole-balance principle. The clients needed additional equity for tuition, but replacing their low-rate first mortgage would have created a large break cost. The solution preserved the existing first mortgage and added new financing behind it. That case does not prove a universal rule; it shows why an existing rate can have economic value that should be measured before refinancing.

A Burlington refinance demonstrates the opposite possibility: the mortgage was replaced even after the prepayment penalty was included because the broader restructuring economics supported the change. The question is therefore total outcome, not whether a penalty or a low rate exists in isolation.

When two offers are close, a disciplined comparison prevents the headline rate from dominating features that may matter more later.