Mortgage Payment Calculator
See your true monthly mortgage payment — principal and interest — plus the total interest you'll pay over the life of the loan.
How the mortgage payment formula works
Every fixed-rate mortgage payment comes from one formula — the same one banks use:
Where P is the loan amount (home price minus down payment), r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12). Early in the loan, the interest portion dominates: on a $320,000 loan at 6.5%, the first payment includes about $1,733 of interest against only $357 of principal. By the final year the ratio has flipped almost completely.
What this payment does and doesn't include
This calculator shows principal and interest (P&I), the core of your payment. A real-world monthly payment often also includes property taxes, homeowner's insurance, HOA fees, and PMI if your down payment is under 20%. Those items vary enormously by location, so no calculator can estimate them accurately without your specifics — budget roughly 1%–2% of the home's value per year for taxes and insurance combined as a starting point.
Down payment vs. rate vs. term — which matters most?
- Rate: on a $320,000 loan over 30 years, dropping from 6.5% to 6.0% saves about $105/month and roughly $38,000 in total interest.
- Down payment: putting an extra $20,000 down on the same loan saves about $126/month and $45,000 in interest — and may eliminate PMI.
- Term: switching from 30 to 15 years at the same rate raises the payment about 47% but cuts total interest by nearly 60%.
Try changing one input at a time in the calculator above and watch total interest — it's the number most buyers underestimate the most.
Frequently asked questions
How is the monthly payment calculated?
With the standard amortization formula M = P × [r(1+r)^n] / [(1+r)^n − 1]. The payment is fixed, but the split between principal and interest shifts every month.
Why does total interest look so high?
Because interest is charged on the full outstanding balance for decades. On a 30-year loan at 6.5%, total interest often exceeds the original loan amount — which is why extra principal payments early on are so effective.
Is a 15-year mortgage better than 30?
Usually a lower rate and dramatically less total interest, but payments are roughly 1.5× higher. Choose based on cash-flow safety, not just the interest math.
Can I pay off my mortgage early?
Yes — most US mortgages allow extra principal payments without penalty, but check your loan terms. One extra payment per year on a 30-year loan typically shortens it by 4–6 years.