Free Mortgage Calculator (2026)

What Is a Mortgage Calculator?

A mortgage calculator is a financial planning tool that estimates your monthly home loan payment based on the property price, down payment, interest rate, and loan term. Unlike a basic loan calculator, a comprehensive mortgage calculator factors in additional costs that homeowners face each month — including property taxes, homeowner’s insurance, and private mortgage insurance (PMI) when your down payment is below 20%. These four components are collectively known as PITI: Principal, Interest, Taxes, and Insurance.

Whether you are a first-time homebuyer exploring your options, a current homeowner considering a new purchase, or a real estate investor analyzing potential deals, understanding your total monthly mortgage obligation is the foundation of sound financial planning. Our mortgage calculator gives you an instant, detailed breakdown so you can compare scenarios, set realistic budgets, and negotiate with confidence.

How Does a Mortgage Calculator Work?

Our calculator requires four primary inputs to generate your payment estimate:

• Home Price: The total purchase price of the property you are considering.
• Down Payment: The amount you plan to pay upfront, expressed as a dollar amount or percentage of the home price.
• Interest Rate: The annual interest rate offered by your lender (typically expressed as a fixed APR).
• Loan Term: The repayment period — commonly 15 or 30 years for residential mortgages.

From these inputs, the calculator computes your monthly principal and interest payment using the standard amortization formula. It then estimates property taxes (based on a national average of approximately 1.1% of home value annually), homeowner’s insurance (roughly 0.35% annually), and PMI (if your down payment is less than 20%). The result is a comprehensive monthly payment figure that reflects your actual housing cost.

The Mortgage Payment Formula

The core formula for calculating the monthly principal and interest payment on a fixed-rate mortgage is:

M = P × [r(1 + r)^n] / [(1 + r)^n − 1]

Where:

• M = Monthly payment (principal and interest only)
• P = Loan principal (home price minus down payment)
• r = Monthly interest rate (annual rate ÷ 12)
• n = Total number of payments (loan term in years × 12)

For the total PITI payment, you then add estimated monthly property taxes, insurance, and PMI to the principal and interest amount.

Step-by-Step Example

Let’s walk through a realistic scenario:

• Home Price: $385,000
• Down Payment: $38,500 (10%)
• Loan Amount (P): $346,500
• Interest Rate: 6.75% annually → 0.5625% monthly (r = 0.005625)
• Loan Term: 30 years → 360 payments (n = 360)

Applying the formula:

M = $346,500 × [0.005625 × (1.005625)^360] / [(1.005625)^360 − 1]

M = $346,500 × [0.005625 × 7.5014] / [7.5014 − 1]

M = $346,500 × 0.04220 / 6.5014 = $346,500 × 0.006491 ≈ $2,247

Add estimated monthly costs:

• Property Tax: $385,000 × 1.1% ÷ 12 ≈ $353
• Homeowner’s Insurance: $385,000 × 0.35% ÷ 12 ≈ $112
• PMI (10% down): $346,500 × 0.55% ÷ 12 ≈ $159

Total PITI Payment: $2,247 + $353 + $112 + $159 = $2,871 per month

Over 30 years, you would pay approximately $808,920 in principal and interest alone — meaning roughly $462,420 goes toward interest. This is why even small rate reductions can save you tens of thousands of dollars.

When Should You Use a Mortgage Calculator?

• Before house hunting: Determine your comfortable price range based on your budget and desired monthly payment.
• Comparing interest rates: See how a 0.25% or 0.50% rate difference translates into real monthly and lifetime dollar amounts.
• Evaluating down payment options: Compare 5%, 10%, and 20% down payments to understand how each affects your monthly obligation and total interest cost.
• Choosing between 15-year and 30-year terms: Shorter terms mean higher payments but dramatically lower total interest.
• Preparing for pre-approval: Know your numbers before meeting with a lender to negotiate from a position of knowledge.

Tips for Getting Accurate Results

• Use your actual pre-qualified rate: Online average rates are general — use the rate your lender has quoted you for the most accurate estimate.
• Check local property tax rates: Tax rates vary dramatically by county and state (from 0.28% in Hawaii to over 2.2% in New Jersey). Look up your specific county rate.
• Get a real insurance quote: Homeowner’s insurance costs depend on location, home age, construction type, and coverage level.
• Remember closing costs: This calculator estimates your monthly payment, but you’ll also need 2-5% of the purchase price for closing costs at signing.
• PMI isn’t permanent: Once you reach 20% equity (either through payments or appreciation), you can request PMI cancellation — lowering your monthly payment.
• Don’t forget HOA fees: If buying in a community with a homeowner’s association, add those monthly dues to your PITI total for a complete picture.

Key Takeaways

• Your total monthly housing cost (PITI) is always higher than just the principal and interest payment — taxes, insurance, and PMI add 15-30% to the base amount.
• A 30-year mortgage at 6.75% means you pay roughly 1.3× the original loan amount in interest over the full term.
• Putting 20% down eliminates PMI and reduces your monthly payment by $100-$300+ depending on the loan size.
• Even a 0.25% rate reduction on a $350,000 loan saves approximately $18,000 over 30 years.