How your mortgage payment is calculated
A fixed-rate mortgage 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, and n is the number of monthly payments. This calculator shows principal and interest only — your actual payment may also include property taxes, homeowners insurance, and HOA fees.
Why a shorter term can save you a fortune
A 15-year loan has higher monthly payments but dramatically less total interest, because you're borrowing the money for half as long. Try switching the term above to see the difference in the "total interest paid" figure — it's often tens or even hundreds of thousands of dollars.
Before you buy
Mortgage rates
Even a 0.25% lower rate can save thousands over the life of the loan.
Compare lenders →Refinance check
If rates have dropped since you bought, refinancing could lower your payment.
Check eligibility →Frequently asked questions
Does this include taxes and insurance?
No — it shows principal and interest only. Add roughly 1–1.5% of the home's value per year for taxes and insurance to estimate your full monthly housing cost.
How much should my down payment be?
20% lets you avoid private mortgage insurance (PMI), but many buyers put down less. A larger down payment lowers both your loan and your monthly payment.
Should I pay extra toward principal?
Extra principal payments shorten your loan and cut total interest. Compare that guaranteed "return" (your mortgage rate) against what you'd earn investing instead.