Mortgage Calculator

A mortgage calculator estimates your monthly home loan payment based on the home price, your down payment, the interest rate, and the loan term. It uses the standard amortization formula that lenders use to figure out a fixed monthly principal-and-interest payment for a fully amortizing loan.

The number you see is just principal and interest (P&I). Real-world mortgage payments usually also include property taxes, homeowner's insurance, and (if your down payment is under 20%) private mortgage insurance — together called PITI. Add roughly 1.5–2.5% of the home value per year for taxes + insurance to estimate the full monthly cost.

Suppose you're buying a $400,000 home with a $80,000 (20%) down payment, a 30-year fixed loan at 6.5%:

• Loan principal: $320,000
• Monthly rate: 6.5% ÷ 12 = 0.005417
• Number of payments: 30 × 12 = 360
• Monthly P&I: $2,022.62
• Total interest paid over 30 years: $408,142

That's the power of compounding interest against you — over the life of the loan you pay more in interest than the original principal. Putting more down or shortening the term dramatically reduces the total interest.

• Before house hunting — figure out a realistic price range that fits your monthly budget.
• Comparing 15-year vs. 30-year — see how a shorter term raises the payment but slashes total interest.
• Down payment decisions — test how an extra $10K, $20K, or hitting 20% to avoid PMI changes the payment.
• Refinance evaluations — compare a new rate to your current mortgage to see if a refi pays off after closing costs.
• Negotiating offers — quickly see how a $5,000 price reduction translates to monthly savings.

• Forgetting taxes & insurance. Your real monthly cost is often 20–40% higher than P&I alone. Use 1.2% of home price per year for property tax in most US states.
• Ignoring PMI. Putting less than 20% down typically adds $100–$300/month in PMI until you cross 20% equity.
• Stretching to the maximum approved. Lenders approve based on debt-to-income; a comfortable budget keeps housing under ~28% of gross income.
• Underestimating closing costs. Add 2–5% of the purchase price for closing costs that aren't in this calculator.
• Comparing rates without comparing APR. APR includes lender fees and is a fairer cross-lender comparison.