Why is my first mortgage payment mostly interest?

Because the entire outstanding balance is accruing interest from day one. Your payment is sized to cover that charge first, with whatever remains going to principal. On a $500,000 loan at 5.15%, the first month's interest alone is $2,123. A monthly payment of $2,951 leaves only $828 for principal.

How do I read an amortization row?

Each row shows payment date, principal paid, interest paid, and remaining balance. Summing principal columns tells you equity build; summing interest shows finance charges over any window you select.

Does a longer amortization change the interest chunk in month one?

The dollar interest on the first balance is the same if the rate and balance match, but a longer amortization lowers the required payment, so principal in month one is smaller.

Where do Canadian renewals show up?

Some calculators mark renewal boundaries separately. Our Canada tabs still show amortization mechanics even if your contract term is shorter than the amortization clock.

Guide

How to read a Canadian amortization schedule

Last updated: April 9, 2026

By Editorial team

A $625,000 Canadian purchase with 20% down leaves a $500,000 mortgage at 5.15% fixed. On a 25-year amortization, the first scheduled month splits about $2,123 of interest versus $828 of principal. Stretch the same balance and rate to 30 years and month-one interest is still about $2,123, but scheduled principal falls to about $590, which is why longer amortizations feel easier on cash flow early on. This guide helps you read those rows before you negotiate prepayment privileges.

The scenario modeled

Both tabs use Canada as country, identical May 2026 start, no taxes or insurance, and a 5-year term label for context. Only the amortization window changes between tabs so you can compare how the schedule front-loads principal paydown.

Input	25-year	30-year
Loan balance	$500,000	$500,000
Rate	5.15% fixed	5.15% fixed
Amortization	25 years	30 years
Payment frequency	Monthly	Monthly

The findings

Total interest over the full 25-year schedule comes to about $385,000. On the 30-year path, that rises to roughly $477,000, a difference of $91,500, because 60 extra months of outstanding balance keeps generating interest charges even though the rate and the monthly interest math look similar in the early years. The month-one interest charge is identical at both amortizations because the balance and rate are the same. What differs is how fast the principal column grows: on the 25-year schedule, each payment retires $238 more in principal from day one.

	25-year	30-year	Reading
Interest in month 1	$2,123	$2,123	Same rate and balance
Principal in month 1	$828	$590	Shorter amort wins equity pace
Total interest (full schedule)	$385,260	$476,823	$91,563 more on 30-year

Canadian context

Canadian mortgage interest is compounded semi-annually by law under the Interest Act, not monthly as in the US. Every row in a Canadian amortization schedule reflects that convention, which produces slightly different principal splits than US monthly compounding on the same nominal rate. In practice, the difference is small for any individual payment but compounds meaningfully over a 25 or 30-year schedule. When comparing broker quotes, confirm both sides use Canadian semi-annual compounding before trusting the totals.

Source: Government of Canada, "Interest Act, R.S.C. 1985, c. I-15, Section 6," accessed April 2026. URL: https://laws-lois.justice.gc.ca/eng/acts/I-15/section-6.html

When this explainer applies, and when it does not

Use it when you are decoding a broker's PDF schedule, want to verify how much equity you have actually built versus how much interest you have paid, or are approaching renewal and trying to understand your remaining balance. It is particularly useful if you are within five years of renewal and weighing whether to shorten your amortization.

It is incomplete when your situation involves skip payments, blended rate increases on renewal, or CMHC insurance premiums rolled into the balance. Those items affect the schedule in ways the basic P&I grid does not capture. Fold them in manually, or use the amortization vs term article if you are still deciding between a 25 and 30-year schedule in the first place.

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Frequently asked questions

Why is my first mortgage payment mostly interest?: Because the entire outstanding balance is accruing interest from day one. Your payment is sized to cover that charge first, with whatever remains going to principal. On a $500,000 loan at 5.15%, the first month's interest alone is $2,123. A monthly payment of $2,951 leaves only $828 for principal.
How do I read an amortization row?: Each row shows payment date, principal paid, interest paid, and remaining balance. Summing principal columns tells you equity build; summing interest shows finance charges over any window you select.
Does a longer amortization change the interest chunk in month one?: The dollar interest on the first balance is the same if the rate and balance match, but a longer amortization lowers the required payment, so principal in month one is smaller.
Where do Canadian renewals show up?: Some calculators mark renewal boundaries separately. Our Canada tabs still show amortization mechanics even if your contract term is shorter than the amortization clock.