Ontario Mortgage Calculator

Important note

Your mortgage is not the only cheque on closing day. Ontario land transfer tax is charged in brackets — 0.5% on the first $55,000 of the price, 1% up to $250,000, 1.5% up to $400,000 and 2% above that — so a $500,000 home owes $6,475, payable in cash at closing (it cannot be added to the mortgage). Buying inside the City of Toronto adds a second, nearly identical municipal land transfer tax, making it $12,950 all-in on the same $500,000. First-time buyers can claim back up to $4,000 of the provincial tax and up to $4,475 more of the Toronto tax. None of that is in the payment above: CMHC suggests budgeting closing costs of roughly 1.5%–4% of the purchase price on top of your down payment.

How this mortgage calculator works

This calculator turns four inputs — home price, down payment, annual rate and amortization — into a monthly mortgage payment estimate. First it computes the principal: P = home price − down payment (floored at zero, so a down payment larger than the price never yields a negative loan). Then it applies the standard amortization formula M = P × r(1+r)^n ÷ ((1+r)^n − 1), where r is the monthly rate (annual rate ÷ 100 ÷ 12) and n is the number of monthly payments (years × 12); a 0% rate simply gives P ÷ n. From that payment it derives the other outputs: total paid over the full amortization (M × n), total interest (total paid − P), and loan-to-value (P ÷ price × 100%, shown with one decimal). One caveat: this page compounds interest monthly, while many Canadian lenders quote rates compounded semi-annually, so a real lender quote can differ slightly — this is an educational estimate, not a commitment.

A worked example

Take a concrete 2026 scenario: a $500,000 home, a $100,000 down payment (20%), a 5% annual rate and a 25-year amortization. The loan is $400,000; r = 0.05 ÷ 12 ≈ 0.0041667; n = 300. The formula gives M ≈ $2,338.36 per month. Three hundred payments total $701,508.05, so lifetime interest is $301,508.05 — about 75% of the amount borrowed, which surprises many first-time buyers. Loan-to-value is 80.0% ($400,000 ÷ $500,000), exactly the 20%-down benchmark where mortgage default insurance is typically not required. The example also shows rate sensitivity: at 6% the monthly payment rises by about $239 (to ≈$2,577) and lifetime interest jumps to ≈$373,162. Try both rates in the form above — that sensitivity is why shoppers re-run the math at a slightly higher "stress" rate before signing.

Three tips for using this tool well

• Run at least three rate scenarios — for example 4.5%, 5.5% and 6.5%. Lenders' rates differ and rates move between pre-approval and closing; the spread shows how much risk sits in your payment.
• Test a shorter amortization. Dropping from 25 to 20 years raises the monthly payment but removes five years of interest; the total-interest output shows exactly what that saves.
• Remember what is excluded. This payment covers principal and interest only — budget property tax, home insurance and (for condos) maintenance fees separately when you judge affordability.