Prime Rate Calculator
What a move in the prime rate does to your variable mortgage payment or your home equity line of credit, starting from today's prime as the Bank of Canada publishes it.
Prime today: 4.45% (Bank of Canada, as of October 14, 2026). See it on the Bank of Canada's site ↗ · Prime rate history
If prime moves, what happens to your payment?
Prime today: 4.45% (as of October 14, 2026)
Prime after the change: 4.70% (+0.25%)
Variable-rate mortgage
Blended payment, principal and interest
Monthly payment, compounded monthly, recalculated on the same balance over the same 30-year remaining amortization.
HELOC or secured line of credit
Interest-only payment
Monthly interest here is balance × rate ÷ 12.
Before you rely on these figures
Many variable-rate mortgages keep the payment the same when prime moves and change how much of it goes to interest instead. Some lenders work that way and some do not. The mortgage figures above show the other case: a blended payment that is worked out again when prime moves.
Each lender sets its own prime rate, so yours can differ from the one shown here. A Bank of Canada rate change takes effect the day after the decision, and banks usually move their prime that same day; your lender's notice gives the date of its own change.
Figures are rounded to the cent. The yearly change is worked out before rounding, so it can differ by a few cents from 12 times the monthly change.
Common questions
How does the prime rate calculator work?+
It starts from today's prime as the Bank of Canada publishes it, adds your own spread (for example prime minus 0.50% or prime plus 1%), and shows your rate and payment before and after the move you pick. A variable-rate mortgage is worked out as a payment of principal and interest on the same balance over the same remaining amortization. A home equity line of credit is shown paying interest only: the balance times the rate, divided by 12.
Will my mortgage payment change when prime changes?+
It depends on your mortgage. With adjustable payments, the payment changes when the rate does. With fixed payments, the payment stays the same and the split changes: when the rate goes up, more of each payment goes to interest and less to the principal. Your contract lists the trigger point at which your lender may raise the payment.
When does a prime rate change take effect?+
A Bank of Canada rate change takes effect the day after the announcement, and banks usually move their prime that same day. Your lender's own notice gives the date of its change.
Why is my bank's prime rate different from the one shown?+
Each lender sets its own prime rate. The figure here is the one the Bank of Canada publishes each week: the most typical prime posted by the six largest banks. Check your lender's own figure and put it in if it differs.
How is a HELOC rate set?+
Most home equity lines of credit have a variable rate based on the lender's prime, for example prime plus 1%, and you pay interest only on the amount you have borrowed. Your lender may also ask for part of the principal with each payment; the calculator shows the interest-only case.
Case Studies — files like this
Anonymized case studies from our files. Names and identifying details removed.
- Case study · Residential / AlternativeA COVID Income Dip and a Collection: An Alternative Lender's Open Equity Line at 73% in DeltaA film location scout with a COVID income dip and a collection already cleared: an alternative lender's open equity line at 9.99% in 2022, behind the first mortgage at about 73% of the Delta home's value, paid out the personal loan and left a cash reserve.Read the file →
- Case study · Residential / PrimeA Mortgage and a Line of Credit in One Refinance: A Major Bank Lent 59% in Maple Ridge and Waived the AppraisalTwo salaries, ratios of about 48% and plans for updates. A major Canadian bank refinanced the Maple Ridge home at 59% in 2023, $550,000 at prime minus 0.75% plus a $100,000 line of credit, with the appraisal waived.Read the file →
- Case study · Residential / PrimeA Single Parent's Maternity-Leave Debt: A Major-Bank Refinance at 48% in North Vancouver Consolidated It and Added a Safety LineA single parent's maternity-leave debt on one salary. A major Canadian bank refinanced the North Vancouver condo in 2025, a mortgage of about $370,000 at prime minus 0.65% plus a $35,000 equity line, together 47.5% of value, paying out the unsecured debt for lower overall payments.Read the file →
Where the rules come from: the prime reading and the day a change takes effect are the Bank of Canada's; how payments and lines of credit respond is the Financial Consumer Agency of Canada's, all read on October 18, 2026. Bank of Canada, Interest rates posted by the major chartered banks (the weekly prime reading) · Bank of Canada, Policy interest rate (a change takes effect the day after its announcement) · Financial Consumer Agency of Canada, Interest on mortgages · Financial Consumer Agency of Canada, Home equity line of credit
Also see: Bank of Canada announcement dates → · Mortgage payment → · Mortgage penalty → · HELOC and equity refinance
Every calculator here is built on published Canadian government rules and lender methodology. This one was built and checked for accuracy on October 18, 2026 — the arithmetic verified against those rules and the page re-read on screen. Rates and thresholds change — we confirm the current numbers for your file before you rely on them.