Money tools
Mortgage Calculator
Estimate your full monthly payment — principal, interest, taxes, and insurance — plus total interest over the life of the loan. Every result shows the formula behind it.
How this calculator works
Your monthly principal & interest comes from the standard amortization formula:
M = P · r(1 + r)n / ((1 + r)n − 1)
- P = loan amount (home price − down payment)
- r = monthly interest rate (annual rate ÷ 12 ÷ 100)
- n = number of payments (loan term in years × 12)
We then add monthly property tax (annual ÷ 12), monthly home insurance (annual ÷ 12), and any HOA dues to get your full monthly payment — the figure lenders call PITI.
Private mortgage insurance (PMI)
PMI is insurance that protects the lender if you default, and conventional lenders require it when your down payment is under 20% of the price. It usually costs 0.3%–1.5% of the loan amount per year, added to your monthly payment (loan × rate ÷ 12). Put down 20% or more and the calculator shows PMI as $0. PMI is not forever: by law you can request cancellation once your balance falls to 80% of the home’s original value, and it ends automatically at 78%. The calculator walks the amortization schedule to estimate the month scheduled payments alone bring your loan-to-value ratio to 80% — extra principal payments, or a higher appraisal, can get you there sooner. Lenders’ exact rules differ. Unsure what you can afford in the first place? Start with how much house can I afford and our take-home pay calculator.
Worked example
On a $400,000 home with $80,000 down (a $320,000 loan) at 6.5% over 30 years, principal & interest is about $2,023/month. Because the down payment is exactly 20%, PMI is $0. Add ~$400 tax and ~$125 insurance and the full payment is roughly $2,548/month, with about $408,000 of total interest. Put down only $40,000 (10%) instead and the $360,000 loan carries PMI of about $150/month at 0.5%, on top of a higher $2,275 principal & interest, until the balance reaches $320,000 — roughly eight years in on the standard schedule.
Tips to lower your payment
- Increase your down payment to shrink the loan and avoid PMI (20%+).
- Shop lenders — even 0.25% off the rate saves thousands over 30 years.
- Consider a shorter term: higher monthly payment, far less total interest.
Frequently asked questions
How is the monthly mortgage payment calculated?
The principal and interest portion 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 HOA dues are added on top.
What is included in the total monthly payment?
This calculator adds principal, interest, property taxes, and homeowners insurance (PITI), plus any monthly HOA dues and, when the down payment is under 20%, private mortgage insurance (PMI). Lenders use this full figure to judge affordability.
Does a bigger down payment lower my payment?
Yes. A larger down payment reduces the loan amount, which lowers both the monthly principal-and-interest and the total interest paid over the life of the loan. Putting down 20% or more also typically avoids private mortgage insurance (PMI).
What is PMI and when does it go away?
Private mortgage insurance protects the lender, not you, on conventional loans with less than 20% down. It typically costs 0.3%–1.5% of the loan amount per year, billed monthly. Under the federal Homeowners Protection Act you can ask your servicer to cancel PMI once your balance reaches 80% of the home’s original value (with a good payment history), and it must be cancelled automatically at 78%. This calculator estimates the month your scheduled payments bring the loan-to-value ratio to 80%; extra payments or a rise in home value can get you there sooner, and lenders’ rules differ.
What is a good mortgage rate right now?
For context, Freddie Mac’s Primary Mortgage Market Survey put the U.S. 30-year fixed average at 7.03% for the week of September 24, 2026. That is an average, not a quote: your rate depends on your credit score, down payment, loan type and term, whether you pay discount points, and which lender you use — quotes for the same borrower can differ by half a percentage point or more. Compare several loan estimates on the same day, and check the current PMMS figure at freddiemac.com/pmms, since this page’s reference is updated manually.
Is this calculator accurate for my exact loan?
It gives a close estimate using standard formulas, but your lender’s figures may differ slightly due to exact PMI pricing, tax assessments, escrow rules, and rounding. Always confirm with a loan estimate from your lender.