Mortgage Calculator
See your monthly payment, total interest, and total cost in seconds.
Principal & interest only. Property tax, insurance, PMI and HOA are not included. For educational purposes — not financial advice.
How the monthly payment is calculated
Your mortgage payment is a fixed amortized payment: the same amount each month, where early payments are mostly interest and later payments are mostly principal. It comes from three inputs — the loan amount (home price minus down payment), the monthly interest rate (annual rate ÷ 12), and the number of payments (years × 12):
M = P · r(1 + r)n / ((1 + r)n − 1)
where P is the loan amount, r is the monthly rate, and n is the number of monthly payments. A higher rate or longer term lowers the monthly payment but raises the total interest you pay over the life of the loan — which is why this calculator shows both.
A worked example
On a $350,000 home with $70,000 down (a $280,000 loan) at 6.5% over 30 years, the monthly principal and interest is about $1,770. Over 30 years you'd pay roughly $357,000 in interest — more than the loan itself. Shortening the term to 15 years raises the monthly payment but can cut total interest by more than half. Try both above to see the trade-off.
What this calculator does not include
Lenders quote a full monthly housing cost (often called PITI) that adds property tax, homeowners insurance, PMI (if your down payment is under 20%), and HOA fees. Those vary by state, lender, and property, so this tool focuses on the part that's pure math — principal and interest — and leaves the local add-ons to your lender's quote.
Tips to lower what you pay
- Put more down. A larger down payment shrinks the loan and can remove PMI at 20%.
- Compare the term. 15-year loans have higher payments but far less total interest.
- Shop the rate. Even 0.25% lower meaningfully changes both payment and total interest.
- Make one extra payment a year. It quietly shaves years off a 30-year loan.