Mortgage Calculator
Estimate your monthly mortgage payment and the total interest over the life of the loan.
How to use
- Enter the home price and your down payment.
- Add the interest rate and loan term.
- See your estimated monthly payment and total interest.
How the Mortgage Calculator works
Estimates the monthly principal-and-interest payment on a home loan, which is the largest and longest-running number in most household budgets.
A mortgage is an amortizing loan, so it uses the same formula as any other: the annual rate becomes a monthly rate, the term becomes a number of months, and the payment is the amount that clears the balance exactly at the end of the term.
M = P × r / (1 − (1 + r)^−n)
Worked example
On a $400,000 loan at 6.5% over 30 years, r = 0.0054167 and n = 360, giving about $2,528 a month. Over the full term that is roughly $910,000 paid on $400,000 borrowed.
Things worth knowing
- This is principal and interest only. Your actual monthly cost also includes property tax, homeowners insurance, and often HOA fees and mortgage insurance — commonly quoted together as PITI.
- A longer term lowers the monthly payment but raises total interest sharply. Compare 15-year and 30-year figures before deciding.
- Rate matters more than most people expect: on a 30-year loan, one percentage point changes the payment by roughly 10%.
Frequently asked questions
Does this include taxes and insurance?
No — it estimates principal and interest only. Add property tax, insurance and HOA separately.
How is the payment calculated?
It uses the standard amortization formula based on principal, monthly rate and number of months.
How much house can I afford?
A common guideline is keeping total housing cost under about 28% of gross monthly income, and all debt payments under about 36%. Lenders vary, and the guideline ignores your other commitments.
Should I pick 15 years or 30?
A 15-year term carries a higher payment but far less total interest and a lower rate. A 30-year term buys flexibility; you can always overpay it like a 15-year loan and stop when money is tight.
What does putting 20% down achieve?
It usually removes private mortgage insurance, which is a pure cost with no benefit to you, and it lowers the amount you are paying interest on.