A mortgage is the largest loan most people ever take, and small differences in rate or term move the total by tens of thousands of dollars. This calculator shows the principal-and-interest portion of your monthly payment, the total interest over the life of the loan, and the full amount you will pay back.
The formula behind your payment
Monthly payment = Loan × Rate/12 × (1 + Rate/12)^n ÷ ((1 + Rate/12)^n − 1), where n is the number of monthly payments. Example: borrowing $300,000 at 6.5% for 30 years gives a monthly payment of about $1,896 and total interest near $382,000 — the interest alone approaches the loan itself over 30 years.
30-year vs 15-year
A 15-year mortgage carries a lower rate and roughly half the total interest, but the monthly payment is much higher (about 1.5× the 30-year payment, not double, because interest is smaller). Choose 30 years for flexibility and invest the difference, or 15 years to be debt-free faster. Run both through the calculator before deciding.
What this calculator does not include
Real mortgage payments usually also include property taxes, homeowners insurance, and PMI when your down payment is under 20%. Lenders call the bundle PITI. Budget roughly 1–2% of the home value per year for taxes and insurance on top of the figures shown here.