Mortgage Calculator
Mortgage payment methodology
Estimate principal-and-interest payments for a fixed-rate mortgage. Home price minus down payment becomes the loan principal. The result does not include property tax, homeowners insurance, mortgage insurance, association fees, closing costs, or changing rates.
Formula and method
Monthly payment = P × [r(1+r)^n] ÷ [(1+r)^n − 1], where P is principal, r is the monthly rate, and n is the number of payments.
Worked example
A $300,000 home with $60,000 down creates a $240,000 loan. At 6.5% for 30 years, principal and interest are about $1,517 per month.
How to interpret the result
The monthly result is principal and interest for a fixed-rate loan. It is useful for comparing loan amount, term, and rate scenarios, but it is not a complete housing budget. Add property taxes, homeowners insurance, mortgage insurance, association dues, maintenance, and any lender fees before comparing the estimate with an affordable monthly payment.
Important limitations
- Enter 0% to model an interest-free loan.
- Compare the result with a lender’s official disclosure before making a decision.
Common questions
Why is a lender quote different?
A lender may include escrow, points, mortgage insurance, closing costs, a different payment date, or a rate based on credit and market conditions. The lender's Loan Estimate is the controlling disclosure.
Does this calculate extra payments?
No. The standard result assumes the scheduled payment for the entire fixed term. Extra principal payments generally reduce interest and shorten the payoff period, but that requires a separate amortization scenario.
Source and further reading
Related tools
Method and examples reviewed September 8, 2026.