Mortgage & financing
Loan Amortization Calculator
Calculate a monthly payment and see how principal and interest change over the selected term. Canadian calculations use nominal interest compounded semi-annually; U.S. calculations use a monthly periodic rate.
Calculate your result
What this calculator estimates
Calculate payments, principal and interest over time. It combines the inputs below to produce Monthly payment. Every assumption remains editable so the estimate can reflect the property, financing and location being evaluated.
Worked example
Using the displayed sample assumptions, the calculator produces $2,779. This is an illustration, not a market quote. Change one input at a time to understand what drives the result.
Inputs and assumptions
- Loan amount — sample input: 500000 currency units
- Annual interest rate — sample input: 4.5 %
- Amortization period — sample input: 25 years
- Balance after year — sample input: 5 years
- Extra monthly principal — optional — sample input: 0 currency units
- Extra principal at each year end — optional — sample input: 0 currency units
How to interpret the result
Compare the payment with your total housing budget, not income alone. Compare a conservative case with an expected case and keep a record of the assumptions used.
Common mistake to avoid
Avoid assuming the lowest advertised rate applies to every borrower. Local definitions, taxes, lending practices and measurement requirements can materially change the result.
Frequently asked questions
What does an amortization schedule show?
It separates payments into principal and interest and shows the remaining loan balance over time.
Why is the early interest amount higher?
Interest is calculated from the outstanding balance, which is usually highest at the beginning of the loan.
Calculation details
Monthly principal and interest uses the level-payment loan formula. U.S. periodic rate = annual nominal rate ÷ 12; Canadian periodic rate = (1 + annual nominal rate ÷ 2)^(1/6) − 1. Extra principal is applied monthly and at each year end. Interest uses the opening balance; the final payment is capped at the amount owed. Taxes, insurance and association fees do not reduce the loan.
Results included
- Monthly payment
- Total interest with entered extra payments
- Balance after selected year
- Principal repaid by selected year
- Interest paid by selected year
- Planned monthly loan payment including extra
- Actual payoff time
- Interest with extra payments
- Interest saved against no-extra schedule
- Annual equivalent
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Reviewed 2026-09-08.