Mortgage Calculator
Payment, mortgage insurance, and total interest for Canadian and US mortgages — each calculated with the compounding its lenders actually use.
of the home price. Minimum for this price:
Common mortgages, already worked out
Each link opens the calculator pre-filled, with a monthly principal-and-interest payment.
About this calculator
A mortgage calculator turns the four big inputs of a home purchase — price, down payment, interest rate, and amortization — into the monthly number you actually pay, plus the lifetime total you will hand the bank in interest. This one is built for both Canadian and US mortgages, with the right compounding for each (Canada compounds semi-annually by law; the US compounds monthly), the right insurance rules (CMHC in Canada, PMI in the US), and the option to layer in property tax and home insurance to see the all-in monthly cost.
What the calculator shows is principal-and-interest at a fixed rate over the chosen amortization. Real mortgages have many more moving parts — fixed-versus-variable, term length, prepayment options, breakage costs — but the monthly payment is the number every other mortgage decision orbits around. Run several scenarios with different rates or amortizations to see which combinations actually fit your budget.
The math: Canadian vs US compounding
The mortgage payment formula is the same everywhere; only the compounding period changes between countries.
Monthly payment = P × r × (1+r)^n ÷ ((1+r)^n − 1), where P is the principal (loan amount), r is the monthly interest rate, and n is the total number of monthly payments.
For a US mortgage, the rate compounds monthly: r = annual_rate ÷ 12. So a 6% annual rate gives r = 0.5% per month.
For a Canadian mortgage, the rate compounds semi-annually by federal law (Interest Act, s. 6). So a 6% "annual" rate is actually 3% per six months, which works out to a slightly lower effective monthly rate than the US version: r = (1.03)^(1/6) − 1 = 0.4939% per month. On a $500,000 mortgage at 6% over 25 years, that semi-annual compounding saves about $33 a month versus the US convention.
Worked example. $500,000 at 5.99% over 25 years, Canadian compounding. r = (1 + 0.0599/2)^(1/6) − 1 = 0.4929% per month, n = 300 months. Payment = 500000 × 0.004929 × 1.004929^300 ÷ (1.004929^300 − 1) ≈ $3,201/month. Over the full 25 years, you pay $3,201 × 300 = $960,300, of which $460,300 is interest — almost as much as the loan itself.
CMHC insurance (Canada). For down payments under 20%, mortgage insurance is mandatory. The premium is a percentage of the loan amount (4% at 5% down, 3.1% at 10%, 2.8% at 15%), added to the principal at closing. PMI (US) works differently — it is a monthly add-on, not capitalised.
Reading the result and avoiding common traps
Use the all-in monthly figure, not just principal-and-interest. Add property tax (typically 0.5–2% of the home's value per year), home insurance ($600–$2,500/year for a typical home), and for condos, monthly fees. A $3,000 principal-and-interest payment can easily become $4,200 once tax, insurance, and condo fees are included.
Double-check the rate type. "5.5%" in Canada is almost always the semi-annual compounded rate quoted under Canadian law; "5.5%" in the US is the monthly compounded APR. Switching country preset in the calculator changes the compounding assumption — confirm you have the right one.
Amortization vs term. In Canada, the term is the period your rate is locked (often 5 years), while the amortization is the total payoff period (often 25). You renew several times before the mortgage is paid off. In the US, the term and amortization are usually the same — a 30-year fixed locks the rate for the full payoff period. This calculator computes the amortization payment; if you have a 5-year Canadian term, you will renegotiate the rate at renewal and the payment may change.
Stress test (Canada). Federally regulated lenders must qualify you at the higher of the contract rate plus 2% or 5.25%. If the calculator says you can afford a 5.5% mortgage, the bank will actually qualify you at 7.5% — so a payment that looks affordable here may not pass the bank's test.
How the mortgage math works
How does the calculation differ for Canada and the US?
The big difference is compounding. A Canadian fixed-rate mortgage compounds interest semi-annually by law — a rule of the federal Interest Act — so a posted rate is not simply divided by 12. A US mortgage compounds monthly, so the monthly rate is the annual rate divided by 12. The two methods give slightly different payments for the same posted rate. The mortgage insurance also differs: Canada uses a one-time CMHC premium added to the loan, while the US uses monthly private mortgage insurance (PMI). Pick your country at the top and the calculator switches both.
What is CMHC insurance? (Canada)
In Canada, mortgage default insurance is required whenever the down payment is under 20% — a high-ratio mortgage. It is offered by CMHC and two private insurers and protects the lender. The premium runs roughly 2.8% at 15% down, 3.1% at 10% down, and 4.0% at 5% down, and is normally added to the loan and paid off over the amortization. With 20% or more down, no premium applies.
What is PMI? (United States)
On a US conventional mortgage with less than 20% down, lenders require private mortgage insurance, or PMI. Unlike Canada’s CMHC premium, PMI is not added to the loan — it is a monthly charge, roughly 0.3% to 1.1% of the loan a year, on top of your principal-and-interest payment. By law it ends once the balance reaches about 80% of the home’s original value, so the calculator estimates how long you pay it and the total cost.
How much down payment do I need?
In Canada the minimum is 5% on the first $500,000 of the price, 10% on any portion from $500,000 to $1,500,000, and 20% above $1,500,000. A US conventional loan can go as low as 3% down for many buyers. In both countries, putting 20% or more down avoids mortgage insurance entirely. The calculator shows the minimum for the country and price you enter and flags a down payment that falls short.
How much does accelerated bi-weekly save?
A regular bi-weekly payment just splits the year into 26 instead of 12, at no extra cost. An accelerated bi-weekly payment is the monthly payment divided by 2 — and because 26 half-payments equal 13 monthly payments instead of 12, you make one extra monthly payment a year. That extra goes straight to principal and typically clears a mortgage several years early, saving tens of thousands in interest. Switch the frequency above to see the exact figures.
Is the mortgage insurance added to my loan?
It depends on the country. A Canadian CMHC premium is normally added to the loan amount and paid off over the full amortization, so the mortgage amount shown is the price minus your down payment, plus the premium. US PMI works differently — it is never financed into the loan; it is a separate monthly charge that stops once you reach 20% equity. The calculator handles each correctly: a financed premium for Canada, a monthly cost with an end date for the US.
What about the stress test or DTI limits?
In Canada, a federally regulated lender qualifies you at the greater of your contract rate plus 2% or 5.25%. In the US, lenders instead look at debt-to-income ratios, commonly around 43%. This calculator shows the payment for the rate you enter — to see your Canadian stress-test payment, simply enter the higher qualifying rate instead. Either way, the core payment here is principal, interest, and mortgage insurance — open Advanced options to add property tax and home insurance and see the all-in monthly figure.
Does a longer amortization save money?
A longer amortization lowers each payment but raises total interest, because the balance is paid down more slowly. In Canada a 25-year amortization is standard; in the US 30 years is the norm. Going from 25 to 30 years can cut the payment by roughly 10%, yet add tens of thousands in interest. Note that an insured Canadian mortgage is normally capped at 25 years, with 30 years allowed only for first-time buyers and new builds. Try the amortization chips above and compare the total-paid figure.
Reviewed 8 June 2026 · methodology cited