How Canadian Mortgage Amortization Works

Summary

A Canadian amortization schedule shows how each mortgage payment splits between principal and interest over the full amortization period (typically 25 years). Canada’s unique semi-annual compounding rule means the effective monthly rate differs from a simple annual-rate-divided-by-12 calculation, and the 5-year term structure means the schedule resets at each renewal.

How it works

The amortization formula (Canadian version)

Canadian fixed-rate mortgages compound semi-annually. The monthly payment formula is the same as the standard amortization formula, but with a different monthly rate:

Effective monthly rate = (1 + annual rate / 2)^(1/6) - 1

Each month:

1. Interest = outstanding balance x effective monthly rate
2. Principal = monthly payment - interest
3. New balance = old balance - principal

Amortization vs term

This distinction is critical in Canada:

At each term renewal, the remaining balance is re-amortized at the new rate for the remaining amortization period. This can significantly change the payment amount if rates have moved.

Why early payments are mostly interest

On a C$522,353 loan at 3.69% over 25 years:

• Month 1: C$1,594 interest, C$1,071 principal (60% interest)
• Month 150 (halfway): roughly equal split
• Month 300 (final): C$8 interest, C$2,657 principal

Accelerated payment options

Canadian lenders commonly offer accelerated payment schedules:

• Accelerated bi-weekly: 26 payments of half the monthly amount (equivalent to one extra monthly payment per year)
• Weekly: 52 payments per year, reducing amortization by 3-4 years on a 25-year mortgage

Worked example

C$400,000 loan, 3.69% fixed, 25-year amortization:

1. Effective monthly rate: (1 + 0.0369/2)^(1/6) - 1 = 0.3051%
2. Monthly payment: C$400,000 x [0.003051 x 1.003051^300] / [1.003051^300 - 1] = C$2,041
3. Month 1: Interest = C$400,000 x 0.003051 = C$1,220. Principal = C$2,041 - C$1,220 = C$821
4. Month 2: Balance = C$399,179. Interest = C$1,218. Principal = C$823
5. Year 1 totals: C$9,953 to principal, C$14,539 to interest
6. Balance after year 5 (first renewal): approximately C$346,500
7. Total interest over 25 years: (C$2,041 x 300) - C$400,000 = C$212,300

Key differences from other markets

• Term renewals reset the schedule. In the UK and US, the amortization schedule runs uninterrupted for the full mortgage term. In Canada, the schedule effectively restarts every 5 years at the new rate, making long-term interest projections uncertain.
• Accelerated bi-weekly payments are a standard Canadian lender feature that shaves 3-4 years off a 25-year amortization. This option is less commonly offered in other markets.