Mortgage Calculator
Estimate your monthly mortgage payment from the home price, down payment, loan term and interest rate, then add property tax, home insurance and PMI for the full picture. Everything runs in your browser — your numbers are never sent anywhere and nothing is stored.
- Principal & interest$0
- Property tax$0
- Home insurance$0
- PMI$0
| Year | Principal paid | Interest paid | Balance |
|---|
How to use the mortgage calculator
- Enter the home price and your down payment — switch the toggle to enter the down payment as a dollar amount or a percentage of the price.
- Set the loan term in years and the annual interest rate.
- Optionally add yearly property tax, home insurance and a PMI rate to see your full monthly payment.
- Results update live. Open the amortization summary to see how your balance, interest and principal change year by year.
The monthly principal & interest comes from the standard amortization formula; taxes, insurance and PMI are spread evenly across the year and added on top to give your estimated full monthly payment.
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Frequently asked questions
How is the monthly mortgage payment calculated?
The monthly principal & interest uses the standard amortization formula: M = P × r × (1+r)^n / ((1+r)^n − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12) and n is the number of monthly payments (years × 12). Property tax, home insurance and PMI are then added on top.
What is included in the full monthly payment?
The full monthly payment is principal & interest plus any monthly property tax, home insurance and PMI (private mortgage insurance). This is often called PITI — Principal, Interest, Taxes and Insurance.
How does the down payment affect the loan?
The down payment is subtracted from the home price to give the loan amount you actually borrow. A larger down payment lowers the loan amount, the monthly payment and the total interest you pay over the life of the loan.
What is PMI and when do I pay it?
PMI (private mortgage insurance) is usually required when your down payment is less than 20% of the home price. It is entered here as a yearly percentage of the loan amount and added to your monthly payment until you build enough equity.
Does the calculator store my numbers?
No. Every calculation runs entirely in your browser — nothing is uploaded to a server and nothing is stored. You can refresh the page to clear all inputs.
Can I use it with a 0% interest rate?
Yes. With a 0% rate the loan amount is simply divided evenly across all the monthly payments, and the calculator handles this case correctly without dividing by zero.