The Mortgage Calculator estimates your monthly home loan payment in USD — including principal and interest — and shows the total interest you will pay over the life of the loan. Enter the home price, down payment, interest rate and loan term to see a full payment breakdown.
Enter the home price, your down payment, the annual interest rate and the loan term in years. The calculator instantly shows your monthly principal-and-interest payment in USD, your loan amount, total interest paid and the full cost of the loan over its lifetime.
Understanding the payment breakdown helps you compare 15-year vs 30-year mortgages, decide how much to put down, and see exactly how a small change in interest rate or term changes the lifetime cost of your home loan.
Use this calculator before beginning any home search — knowing your maximum comfortable monthly payment works backwards to a purchase price ceiling more reliably than relying on a lender's pre-approval figure (which reflects what you qualify for, not necessarily what is sustainable for your budget). It is also invaluable when comparing two loan offers: a slightly different rate may look identical until you run both through the amortization breakdown and see the total interest difference over 25 or 30 years.
The most consequential mistake is confusing the monthly P&I (principal and interest) payment with the actual monthly housing cost. Property taxes, homeowners insurance, and PMI (if the down payment is below 20%) are added on top of P&I — together they often add 20–40% to the base figure. A second error is focusing on the monthly payment rather than the total interest over the loan life: a 30-year loan at 6.5% on a £300,000 mortgage means paying over £190,000 in interest — more than half the home's price again.
A buyer puts £60,000 (20%) down on a £300,000 home at a 4.5% fixed rate over 25 years. The monthly P&I is approximately £1,334, but with council tax, insurance, and service charges, the true monthly housing cost is closer to £1,700. By making one extra monthly payment per year toward principal, they shorten the mortgage by nearly three years and save over £18,000 in interest — a decision this calculator makes visible before the loan is signed.
Monthly Mortgage Payment Formula
M = P × [r(1+r)^n] / [(1+r)^n − 1]
Where M = monthly payment, P = loan amount (home price minus down payment), r = monthly interest rate (annual rate ÷ 12), n = total months (years × 12).
You buy a $400,000 home with 20% down ($80,000) at a 6.5% interest rate for 30 years.
Result: Monthly payment = $2,023 — Total interest over 30 years = $408,280
A common guideline is the 28% rule: your monthly mortgage payment should not exceed 28% of your gross monthly income. On a
PITI: Principal, Interest, Taxes and Insurance. Your lender may also require PMI if your down payment is under 20%.
Private Mortgage Insurance protects the lender if you default. It typically costs 0.5–1% of the loan amount per year until you reach 20% equity.
A 15-year mortgage builds equity faster and saves a large amount in interest, but the monthly payment is roughly 50% higher than a 30-year mortgage at the same rate.
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