Mortgage Calculator

What Is a Mortgage Calculator?

This mortgage calculator shows you exactly what your monthly mortgage payment will be — and how much of it goes to interest versus principal each year. It is the most important tool to use before buying a home. In fact, understanding your mortgage before you sign can save you tens of thousands of dollars over the life of the loan.

Whether you are a first-time buyer or refinancing an existing loan, this mortgage calculator gives you the complete picture — monthly payment, total interest, and a full year-by-year amortisation schedule.

How Does the Mortgage Calculator Work?

This mortgage calculator uses the standard loan amortisation formula to calculate your monthly payment. It then splits each payment into its principal and interest components and tracks your remaining balance year by year.

For example, a $400,000 home with a $80,000 down payment at 6.5% over 30 years produces a monthly payment of approximately $2,023. Furthermore, total interest paid over 30 years is approximately $408,000 — more than the original loan amount.

How to Use This Mortgage Calculator

1. Enter the home price — the full purchase price of the property.
2. Enter your down payment — the cash amount you are contributing upfront.
3. Select your loan term — 15, 20, 25, or 30 years.
4. Enter the annual interest rate — use your lender’s quoted rate or current market rates.
5. Add property tax and insurance — optional, but including them shows your true total monthly housing cost.
6. Click Calculate — your monthly payment, total interest, amortisation schedule, and full breakdown appear instantly.

What Does Your Mortgage Calculator Result Mean?

The mortgage calculator shows three key figures plus a year-by-year amortisation schedule.

• Monthly Payment: Your principal and interest payment each month. If you included property tax and insurance, those are added to this figure.
• Total Interest: The total extra money paid to the lender over the full loan term. This is the true cost of borrowing.
• Total Cost: The full amount paid including down payment, all monthly payments, and all interest. This is the real price of the home.

The amortisation schedule shows how each year’s payments split between principal and interest. In the early years, most of your payment goes to interest. However, as the balance falls, more goes to principal. This shift is gradual but accelerates significantly in the final years of the mortgage.

15-Year vs 30-Year Mortgage — What the Mortgage Calculator Reveals

This is one of the most important decisions in home financing. Use this mortgage calculator to compare both options on your specific loan amount.

30-Year Mortgage

A 30-year mortgage keeps your monthly payment lower. This makes homeownership more accessible month to month. However, you pay interest for twice as long. As a result, total interest on a 30-year mortgage is typically 2–3 times higher than a 15-year mortgage on the same loan.

15-Year Mortgage

A 15-year mortgage has a higher monthly payment — typically 30–40% more than the 30-year equivalent. In contrast, you pay dramatically less total interest. Furthermore, lenders often offer lower interest rates on 15-year mortgages, which compounds the saving further. Use the mortgage calculator to see the exact difference for your loan.

Down Payment and Its Effect on Your Mortgage Calculator Result

Your down payment directly affects your loan amount, monthly payment, and total interest. It also affects whether you need Private Mortgage Insurance (PMI).

• 20% or more: Avoids PMI, lower monthly payment, immediate equity, best total cost. The mortgage calculator will show the lowest interest cost at this level.
• 10–19%: PMI required, higher effective monthly cost. The mortgage calculator does not include PMI — add approximately 0.5–1.5% of loan value annually.
• Less than 10%: Highest PMI cost, least equity, highest total mortgage cost. However, it enables homeownership sooner for those without large savings.

Is This Mortgage Calculator Accurate?

This mortgage calculator is accurate for fixed-rate mortgages. It uses the standard amortisation formula used by all lenders. However, it does not include PMI, closing costs, lender fees, or stamp duty — which vary significantly by location and loan type.

According to the Consumer Financial Protection Bureau (CFPB), understanding the full cost of a mortgage — including all fees and the total interest over the loan term — is essential before committing to any home loan. Use this mortgage calculator as your starting point, then get a full loan estimate from your lender for the complete picture.

Common Mortgage Mistakes This Calculator Helps You Avoid

• Not knowing your total interest cost: Many buyers focus only on the monthly payment. However, this mortgage calculator reveals the full interest cost — which is often larger than the original loan on long terms.
• Choosing the longest term by default: A 30-year term is not always the right choice. Run the mortgage calculator for 15 and 20 years to see if you can afford the higher payment and save significantly on interest.
• Ignoring property tax and insurance: These add significantly to your true monthly housing cost. Include them in this mortgage calculator for a realistic monthly budget figure.
• Not comparing lender rates: A 0.5% difference in interest rate on a $350,000 mortgage saves approximately $30,000 over 30 years. Use this mortgage calculator with multiple rates to see the exact saving.

Mortgage Calculator — Frequently Asked Questions