Mortgage Calculator

The calculator uses the standard amortization formula: P&I = L x r x (1 + r)^n / ((1 + r)^n - 1), where L is the loan amount (home price minus down payment), r is the annual rate divided by 12, and n is the total number of monthly payments. It then adds monthly property tax, home insurance, HOA, and PMI to give you the full monthly total.

Private mortgage insurance (PMI) protects the lender if you default on the loan. This calculator models borrower-paid PMI when your down payment is less than 20% of the home price. A real lender may instead price lender-paid insurance into the rate or use another structure. Annual PMI often runs 0.3% to 1.5% of the loan amount, so on a $350,000 loan that is about $87 to $437 per month. This estimate uses the original loan balance, not the home price.

A 15-year mortgage usually carries a lower interest rate and far less total interest paid, but the monthly payment is often 30% to 50% higher than a 30-year on the same loan, depending on the rate gap. A 30-year lowers your monthly obligation and keeps cash free for other goals, at the cost of more interest over the life of the loan. Run both scenarios in the calculator to see the exact dollar difference for your situation.

There is no universal mortgage-score cutoff. A lender sets its own approval and pricing rules and may impose requirements above a program's minimum. FHA policy generally permits 3.5% down at scores of 580 or higher and 10% down from 500 to 579, subject to lender underwriting. This calculator does not determine eligibility or quote a rate, so compare written Loan Estimates for your actual file.

A widely used guideline is the 28/36 rule: keep your total housing payment (principal, interest, taxes, and insurance) at or below 28% of gross monthly income, and keep all monthly debt at or below 36%. Enter your target home price and realistic taxes and insurance in this calculator, then compare the total monthly payment against your income to see where you land.

The calculator breaks the total into principal and interest (P&I), monthly property tax, homeowners insurance, HOA fees, and PMI when applicable. PITI means principal, interest, property taxes, and homeowners insurance. HOA dues and PMI are separate additions, even when a lender collects some of these costs with the monthly mortgage payment.