About the Mortgage calculator
This mortgage calculator works out what you will actually pay each month for a home, not just the loan itself. It adds principal and interest to monthly property tax, homeowners insurance, PMI and any HOA fee, then shows the split in a chart and a year-by-year amortization schedule.
You also see the loan amount, total interest, the total of all payments and when the loan is paid off. Add an extra monthly payment and it reports the interest and time you save. Every result comes with step-by-step working using your own numbers, so you can check each line.
How to use it
- Enter the Home price and your Down payment as a percent of that price.
- Type the Interest rate and pick a Loan term from 10 to 30 years.
- Enter Property tax as a yearly percent of the home price, plus Home insurance per year.
- Set the PMI rate (it only applies when your down payment is under 20%) and any HOA fee per month.
- Optionally add an Extra payment per month to see how much interest and time it saves.
- Read the monthly total, the payment breakdown and the yearly amortization schedule.
The formula
The loan amount is the price minus the down payment. The principal and interest part uses the standard fixed-rate payment formula:
M = P × r(1 + r)^n ÷ ((1 + r)^n − 1)
- M — monthly principal and interest
- P — loan amount (home price × (1 − down payment %))
- r — monthly interest rate (annual rate ÷ 12 ÷ 100)
- n — number of payments (years × 12)
The other costs are added on top:
Total = M + (price × tax% ÷ 12) + (insurance ÷ 12) + (P × PMI% ÷ 12) + HOA
PMI is included only when the down payment is below 20%. The calculator walks through the amortization schedule and finds the payment where the balance first falls to 80% of the home price, and shows PMI as lasting until that payment.
What is PMI and when does it stop?
Private mortgage insurance protects the lender, not you. Conventional lenders commonly require it when you put down less than 20% of the price. It is usually quoted as a yearly percentage of the loan amount, which is how this calculator charges it.
PMI does not last forever. On a conventional loan you can generally ask the lender to cancel it once your balance reaches 80% of the home’s original value, and it typically ends automatically a little later, at 78%. The calculator uses the 80% point, so the result row tells you roughly which payment number PMI should drop off. Paying extra each month gets you there sooner.
Government-backed loans such as FHA loans use their own mortgage insurance premium with different rules, so check your loan estimate if you are not using a conventional loan.
Worked example: how an extra payment changes the picture
Take a $400,000 home with 20% down, a 6.5% rate and a 30-year term. The loan is $320,000 and principal and interest come to about $2,022.62 a month. Add 1.1% property tax ($366.67 a month) and $1,500 a year of insurance ($125 a month), and the full payment is about $2,514.28.
Over 30 years that loan costs roughly $408,000 in interest. Now add $200 a month as an extra payment. Every extra dollar goes straight to principal, so less interest builds up in each later month. The loan is paid off in about 23 years 5 months, and the interest saved is a little over $105,000.
Extra payments work best early, when the balance is largest. Check that your lender applies them to principal and has no prepayment penalty.
Frequently asked questions
What is included in a monthly mortgage payment?
Most lenders collect principal and interest plus escrow for property tax and homeowners insurance, often called PITI. PMI and HOA dues may be added on top, and this calculator includes all of them in the monthly total.
How do I turn my property tax bill into a percent?
Divide the yearly tax bill by the home price and multiply by 100. A $4,400 bill on a $400,000 home is 1.1%.
Does the monthly payment include my extra payment?
No. The headline payment is what you owe each month; the extra payment is shown separately through the shorter payoff time and the interest saved.
Why does so much of each early payment go to interest?
Interest is charged on the remaining balance, which is highest at the start. As the balance shrinks, more of the same fixed payment goes to principal, which the yearly schedule makes easy to see.
Should I choose a 15-year or 30-year term?
A 15-year loan has a higher payment but usually a lower rate and far less total interest. Try both terms here and compare the monthly total against the total interest to see the trade-off.
Last updated October 24, 2026. Results are estimates for education and planning — see our disclaimer.