Mortgage Calculator
Estimate mortgage payments and the impact of extra payments.
20.0% of the purchase price
Applied directly to principal to shorten the loan.
Results
Monthly payment
$2,022.62
Principal and interest, excluding taxes and insurance
Total interest
$408,142.38
Over 30 years
Total paid
$728,143.20
Principal plus all interest
Loan amount
$320,000.00
20.0% down
Remaining balance over time
Summary
- Purchase price
- $400,000.00
- Down payment
- $80,000.00
- Amount financed
- $320,000.00
- Monthly principal & interest
- $2,022.62
- Number of payments
- 360
- Total interest
- $408,142.38
Estimate only. Property taxes, homeowners insurance, HOA fees, and mortgage insurance are not included, so your real total payment will be higher. Rates and terms vary by borrower and location.
How to use the mortgage calculator
The mortgage calculator estimates your monthly payment and shows the true cost of borrowing over the full term. It takes the purchase price, your down payment, the interest rate, and the length of the loan, then applies the standard amortisation formula to produce a payment you can compare against a lender's quote.
The down payment is the first number that changes everything. Every dollar you put down reduces the amount you borrow, and interest is charged on the outstanding balance, so a larger down payment lowers the payment and the total interest at the same time. A 20% down payment on a $400,000 home means borrowing $320,000 rather than $360,000, which is a meaningful difference over thirty years.
The interest rate is the other variable that dominates the result, and small differences compound. A quarter of a percentage point on a $320,000 thirty-year loan is not a trivial amount over the life of the mortgage, which is why it is worth shopping rates properly rather than accepting the first offer. Rates also depend on your credit profile and on how much of a down payment you make.
The term is the third lever, and the trade-off is direct. A fifteen-year mortgage has a higher monthly payment and dramatically less total interest than a thirty-year mortgage on the same balance. Whether it is worth it depends on how much you can comfortably afford each month and what else you might do with the difference in monthly cash flow.
Adding an extra monthly payment shows how sensitive the schedule is to that decision. Because extra payments go straight to principal, a few hundred dollars a month can remove years from the loan and tens of thousands of dollars from the interest total. The chart shows the remaining balance over time so you can see how quickly it comes down.
One important caveat: this calculator covers principal and interest only. Your actual monthly payment will be higher once property taxes, homeowners insurance, and any mortgage insurance are added, and none of those are included here. Use the figure as a reliable baseline for the loan itself, then add the other costs from your lender's estimate.
Frequently asked questions
How is a monthly mortgage payment calculated?
The payment is calculated with the standard amortisation formula: M = P × r(1+r)^n / ((1+r)^n - 1), where P is the amount borrowed, r is the monthly interest rate, and n is the number of monthly payments. The result covers principal and interest only.
Does this include property taxes and insurance?
No. This calculator shows principal and interest. Property taxes, homeowners insurance, HOA dues, and mortgage insurance are separate and are not predictable without knowing your location, the property, and your lender's specific requirements.
What is the 20% down payment rule?
It is not a legal requirement in most places, but lenders typically require private mortgage insurance (PMI) on loans with less than 20% down. That insurance adds to your monthly payment and can be removed once you reach the cancellation threshold, usually by reaching 20% equity.
How much more does a 15-year mortgage cost per month?
Usually substantially more per month, and considerably less in total. The shorter term means you pay more principal in each payment and less interest overall. The calculator shows both options side by side so you can see the real trade-off rather than guessing.
Is it better to pay extra or to invest the difference?
Paying extra guarantees a return equal to your mortgage rate, which is often higher than most conservative investment returns. Investing offers potentially higher returns but comes with risk. The right answer depends on your emergency savings, your risk tolerance, and the interest rate on your mortgage. Our loan versus investment calculator compares the two directly.
How accurate is this estimate?
It is accurate for the loan itself, assuming a fixed rate and monthly payments. Your lender will also include taxes, insurance, and any fees, so your actual payment and total cost of borrowing will be higher than what this tool shows.
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