Canadian Amortization Calculator

The rate every row of your schedule actually uses

Every line of an amortization schedule splits one payment into interest (balance × monthly rate) and principal (the remainder). Get the monthly rate wrong and every single row is wrong, compounding the error to the end of the table. The Interest Act, s. 6 requires that a mortgage with blended payments state its rate "calculated yearly or half-yearly, not in advance" — Canadian lenders use the half-yearly option, so the monthly rate for every row is r = (1 + j/2)^(1/6) − 1, not the simple j/12 a US amortization table would use. Section 7 of the same Act adds a second rule worth knowing: if the rate actually stated in your mortgage is lower than what would otherwise apply, only that lower stated rate can be charged — the Act sets a ceiling in the borrower's favour, not just a formula.

Worked schedule: how 25 vs. 30 years changes both the balance and the total

Take a C$720,000 purchase with 15% down (C$108,000), a 5.35% contract rate. The base loan is C$612,000 at 85% loan-to-value, which lands in CMHC's 80.01–85% premium tier at 2.80% of the loan amount.

The 30-year schedule starts C$1,224 higher in row 1 because of the surcharge alone, before a single payment is made. It then lowers the monthly payment by roughly C$288 — but because every one of those 360 rows is charging interest on a slower-shrinking balance, the total paid across the full schedule is about C$123,000 higher than the 25-year table, even though the rate never changed. That gap is the schedule doing exactly what it's supposed to: showing you the true cost of stretching the same debt over more rows.

The 30-year amortization itself isn't available to every insured borrower. CMHC's own premium information for homeowner loans states that any amortization period beyond 25 years is subject to a 0.20% surcharge, separate from the loan-to-value premium tier itself — the two numbers add together rather than replacing each other. CMHC's 2024 notice on the surcharge ties the 30-year option and its 20-basis-point premium surcharge to first-time buyers purchasing newly constructed homes, effective August 1, 2024. FCAC's own explainer describes the broader amortization ceiling for insured mortgages as 30 years for first-time buyers and/or new-build purchasers with under 20% down, and 25 years for other insured-adjacent cases with under 20% down — for a down payment of 20% or more, the lender sets the maximum rather than a regulator.

Why the early rows of your schedule are interest-heavy

In the 25-year schedule above, the first payment of about C$3,786 splits into roughly C$2,774 of interest and only C$1,012 of principal — 73% of that first payment services interest on the C$629,136 opening balance under the semi-annual formula from the previous section. That ratio flips gradually as the balance shrinks with every row, which is the normal shape of any amortizing loan; it is not specific to Canada. What is specific to Canada is the starting balance itself: because CMHC's premium is calculated on the loan amount and rolled in before row 1, a lower down payment does not just mean a bigger loan, it means a larger insurance premium stacked on top of that loan, which pushes even more of your early payments toward interest rather than principal.

CMHC will not insure a schedule that starts above its price ceiling: eligibility for homeowner mortgage loan insurance requires the purchase price be below C$1,500,000, with a minimum down payment of 5% on the first C$500,000 of price plus 10% on the portion between C$500,000 and the price cap. Above that price, or below that down payment, there is no CMHC row to add to the schedule — the mortgage is uninsurable at any premium.

What the schedule leaves out on purpose

The CMHC premium rolls into row 1 of your schedule because it's financed with the mortgage. The tax on that premium does not, and never appears anywhere in the 300 or 360 rows above. CMHC states plainly that Ontario, Quebec and Saskatchewan charge provincial sales tax on the premium and that the tax "cannot be added to the loan amount" — on the C$17,136 premium in the 25-year example, an Ontario buyer's 8% PST is C$1,370.88, due in cash at closing, not amortized. A schedule that only shows financed amounts will always understate what you actually spend to close.

Shortening the schedule you just built

This calculator's schedule assumes you make only the regular payment for the full term shown. Two ways to shorten it without changing your rate: switch payment frequency on the biweekly mortgage calculator, which reproduces the same semi-annual formula against an accelerated schedule, or model a lump sum or extra monthly payment on the mortgage payoff calculator — both apply directly against the opening principal this page calculates, including the CMHC premium if your mortgage is insured.

Why the payment gap between 25 and 30 years can decide whether you qualify

The roughly C$288 lower monthly payment on the 30-year schedule above isn't just a cash-flow convenience — it changes the ratio a lender actually qualifies you on. CMHC's own general requirements for homeowner mortgage loan insurance state that gross debt service (GDS) shouldn't exceed 39% and total debt service (TDS) shouldn't exceed 44% of gross household income. Take a household earning C$11,500 gross per month with no other debt: the 25-year schedule's C$3,786 payment runs a 32.9% GDS ratio; the 30-year schedule's roughly C$3,498 payment runs about 30.4%. Both clear the 39% ceiling here, but a household closer to the line — with a car payment or student loan already eating into TDS room — can find that the longer amortization's lower payment is what keeps them under 39%/44% at all, not just a nice-to-have.