What is mortgage amortization?
**Mortgage amortization is the process of paying off your mortgage through regular scheduled payments over a fixed period.** Each payment is split into two portions: one that reduces your outstanding principal, and one that covers the interest charged on the remaining balance.
The amortization period is the total time it takes to pay off the mortgage in full, assuming you maintain the same interest rate and payment amount. In Canada, the standard maximum amortization period is 25 years for insured mortgages and 30 years for uninsured mortgages. Since December 15, 2024, first-time homebuyers and purchasers of newly constructed homes can also access 30-year amortization for insured mortgages.
An amortization schedule is a table that lists every single payment over the life of your mortgage. For each payment, it shows the payment number, date, total payment amount, principal portion, interest portion, and remaining balance. This schedule lets you see exactly when your mortgage will be paid off and how much total interest you will pay.
How to read an amortization schedule
**The key insight from any amortization schedule is the shift from interest-heavy to principal-heavy payments over time.** In the first year of a $400,000 mortgage at 5% over 25 years, approximately 63% of each monthly payment goes to interest and only 37% to principal. By year 20, this reverses: about 82% goes to principal and 18% to interest.
Each row in the schedule shows a single payment. The interest portion is calculated by multiplying the remaining balance by the per-period interest rate. The principal portion is whatever is left after subtracting the interest from the total payment. After each payment, the balance decreases by the principal portion.
The year-by-year summary groups these individual payments into annual totals. The interest-to-principal ratio column shows how many dollars of interest you pay for every dollar of principal in that year. A ratio above 1.0 means you are paying more interest than principal. A ratio below 1.0 means you are paying more principal than interest. Most mortgages cross the 1.0 threshold somewhere between year 8 and year 15, depending on the rate and amortization period.
| Year | Principal Paid | Interest Paid | Interest:Principal Ratio | End Balance |
|---|---|---|---|---|
| 1 | $8,032 | $19,846 | 2.47 | $391,968 |
| 5 | $9,805 | $18,073 | 1.84 | $355,081 |
| 10 | $12,616 | $15,262 | 1.21 | $296,895 |
| 15 | $16,228 | $11,650 | 0.72 | $221,803 |
| 20 | $20,874 | $7,004 | 0.34 | $124,903 |
| 25 | $26,494 | $1,384 | 0.05 | $0 |
Understanding the principal vs interest ratio over time
**In the early years of your mortgage, interest dominates each payment because the outstanding balance is at its highest.** As you make payments and reduce the principal, the interest portion shrinks and the principal portion grows. This is the fundamental characteristic of an amortizing loan.
The interest-to-principal ratio is a useful metric for understanding where you stand in your mortgage journey. On a $400,000 mortgage at 5% over 25 years with monthly payments, the ratio starts at approximately 2.47 in year 1 (you pay $2.47 in interest for every $1 of principal). It crosses 1.0 around year 12, meaning you finally start paying more principal than interest. By year 25, the ratio drops to approximately 0.05.
This ratio is especially relevant at renewal time. If you are 10 years into a 25-year amortization, you have already paid the majority of the interest cost. Refinancing or extending the amortization at this point would reset the ratio, causing you to pay more interest again. Understanding where you stand on the amortization curve helps you make informed decisions about prepayments, refinancing, and renewal negotiations.
Impact of rate changes at mortgage renewal
**When your mortgage term ends (typically every 5 years), your payment is recalculated based on the new interest rate and your remaining balance and amortization.** A rate increase at renewal raises your payment and shifts the interest-to-principal ratio back toward interest. A rate decrease has the opposite effect.
For example, if you started with a $400,000 mortgage at 4% over 25 years and your rate increases to 6% at your first renewal (after 5 years), your monthly payment jumps from $2,096 to approximately $2,507 on the remaining $343,000 balance over 20 years. The total additional interest cost over the remaining amortization is roughly $55,000 compared to staying at 4%.
This is why the federal mortgage stress test exists: it ensures you can afford payments at a rate at least 2% higher than your contract rate (or 5.25%, whichever is greater). Reviewing your amortization schedule before renewal helps you understand the financial impact of different rate scenarios and decide whether to lock in a fixed rate or choose variable.
The amortization calculator above lets you model these scenarios. Change the interest rate to see how it affects your payment amount, total interest, and the number of payments needed to pay off the mortgage.
How extra payments reshape your amortization schedule
**Extra payments go directly to reducing your principal, which shrinks the balance that accrues interest on every subsequent payment.** Even modest extra payments compound into significant savings because they reduce the principal for the entire remaining life of the mortgage.
On a $400,000 mortgage at 5% over 25 years with monthly payments, adding just $200 per month in extra payments saves approximately $54,000 in total interest and shortens the amortization by about 5 years. The effect is most powerful in the early years when the balance is highest.
Most Canadian lenders allow annual prepayment privileges of 10% to 20% of the original mortgage principal without penalty. You can also increase your regular payment by a similar percentage. On a $400,000 mortgage, that means up to $40,000 to $80,000 in extra payments per year, penalty-free ([FCAC](https://www.canada.ca/en/financial-consumer-agency/services/mortgages/reduce-prepayment-penalties.html)).
Before making large prepayments, check your mortgage contract for limits. Exceeding your annual privilege on a closed mortgage triggers a penalty: the greater of three months' interest or the Interest Rate Differential (IRD) for fixed-rate mortgages, or three months' interest for variable-rate mortgages.
Worked example: building an amortization schedule
**Step 1: Set the mortgage details.** You have a $400,000 mortgage at 5.00% with a 25-year amortization and monthly payments.
**Step 2: Calculate the effective rate.** Using Canadian semi-annual compounding: Effective Annual Rate = (1 + 0.05/2)^2 - 1 = 5.0625%. Monthly rate = (1.050625)^(1/12) - 1 = 0.4124%.
**Step 3: Calculate the monthly payment.** Payment = (0.004124 x $400,000) / (1 - (1.004124)^(-300)) = $2,326 per month.
**Step 4: Build payment #1.** Interest = $400,000 x 0.004124 = $1,650. Principal = $2,326 - $1,650 = $676. New balance = $400,000 - $676 = $399,324.
**Step 5: Build payment #2.** Interest = $399,324 x 0.004124 = $1,647. Principal = $2,326 - $1,647 = $679. New balance = $399,324 - $679 = $398,645. Each subsequent payment reduces the balance slightly more than the previous one.
**Step 6: Review year 1 totals.** After 12 payments: total paid = $27,912, principal repaid = $8,253, interest paid = $19,659, remaining balance = $391,747. The interest-to-principal ratio for year 1 is 2.38, meaning you paid $2.38 in interest for every $1 of principal.
Frequently asked questions
What is the difference between an amortization schedule and a mortgage payment calculator?
**A mortgage payment calculator tells you your payment amount. An amortization schedule shows you every single payment over the life of the mortgage, including how each one splits between principal and interest.** The amortization schedule is the full roadmap of your mortgage, letting you see your balance at any point in time and how much total interest you will pay.
How does Canadian semi-annual compounding affect the amortization schedule?
**Semi-annual compounding means your stated annual rate compounds twice per year, not monthly or daily.** A 5.00% nominal rate in Canada produces an effective annual rate of 5.0625%, while the same 5.00% in the US (monthly compounding) produces 5.1162%. This means Canadian borrowers pay slightly less interest than US borrowers at the same nominal rate, and the amortization schedule reflects this lower effective rate.
When does the interest-to-principal ratio drop below 1.0?
**On a typical 25-year amortization at 5%, the crossover point is around year 12.** Before that point, you pay more interest than principal with each payment. After it, more of each payment goes to reducing your balance. At lower rates, the crossover happens earlier. At 3%, it occurs around year 9. At 7%, it shifts to around year 15.
How much total interest will I pay on a $400,000 mortgage at 5% over 25 years?
**Approximately $297,000 in total interest, bringing your total cost to roughly $697,000.** With monthly payments of about $2,326, the first year alone costs approximately $19,660 in interest. Making $200/month in extra payments would reduce total interest to approximately $243,000 and shorten the amortization by about 5 years.
Does accelerated bi-weekly really save that much interest?
**Yes. On a $400,000 mortgage at 5% over 25 years, accelerated bi-weekly payments save approximately $40,000 in interest and pay off the mortgage about 3.5 years early.** This works because you make 26 half-payments per year (equivalent to 13 monthly payments instead of 12). That extra payment goes entirely to principal, compounding the savings over the remaining term.
What happens to my amortization schedule when I renew at a different rate?
**Your schedule is completely recalculated.** At renewal, the lender takes your remaining balance and remaining amortization period, applies the new rate, and calculates a new payment. If the rate increased, your payment goes up and the interest portion of each payment increases. If the rate decreased, the opposite happens. The amortization schedule tool above lets you model different rates to prepare for renewal scenarios.
Can I download my amortization schedule?
**You can share your results using the share button, which copies a URL with your exact inputs.** Anyone who opens that link will see the same amortization schedule you generated. For a spreadsheet format, you can manually copy the table data or use the browser's print function to save as PDF.
What is the maximum amortization period in Canada?
**For insured mortgages (down payment under 20%), the standard maximum is 25 years.** Since December 15, 2024, first-time homebuyers and purchasers of newly constructed homes can qualify for 30-year amortization on insured mortgages. For uninsured mortgages (down payment of 20% or more), most lenders offer up to 30 years, and some offer up to 35 years.
How do lump-sum prepayments affect my amortization schedule?
**A lump-sum payment directly reduces your principal balance, which reduces the interest charged on every subsequent payment.** For example, a $10,000 lump sum on a $350,000 balance at 5% saves approximately $412 per year in interest for every remaining year. Over 20 years, that $10,000 lump sum saves roughly $8,240 in total interest. Most Canadian lenders allow annual prepayments of 10% to 20% of the original principal without penalty.
Should I choose a shorter amortization to save interest?
**A shorter amortization saves significant interest but requires higher payments.** A $400,000 mortgage at 5% with a 20-year amortization has a monthly payment of $2,626 (vs $2,326 for 25 years) but saves approximately $64,000 in total interest. A 15-year amortization saves $125,000 but requires $3,143/month. Choose the shortest amortization you can comfortably afford, keeping an emergency buffer.