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.
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. Add ~$400 tax and ~$125 insurance and the full payment is roughly $2,548/month, with about $408,000 of total interest.
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 four parts, often called PITI plus HOA: principal, interest, property taxes, and homeowners insurance, plus any monthly HOA dues. 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).
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 PMI, exact tax assessments, escrow rules, and rounding. Always confirm with a loan estimate from your lender.