Mortgage Calculator
Estimate monthly mortgage payments, total interest, and loan costs based on your home price, down payment, rate, and term.
What This Mortgage Calculator Does
This calculator estimates your monthly mortgage payment based on four key inputs: home price, down payment, interest rate, and loan term. It also provides a breakdown of total interest paid over the life of the loan and the total cost of the mortgage. The goal is to give you a realistic picture of what a specific property might cost you each month and over time.
How Your Monthly Payment Is Calculated
The calculator uses the standard amortization formula for fixed-rate mortgages. Your monthly payment is determined by the loan amount (home price minus down payment), the annual interest rate divided by 12, and the total number of monthly payments (loan term in years multiplied by 12).
The calculation assumes a fixed interest rate for the entire loan term. It does not account for variable-rate mortgages, interest-only loans, or other non-standard structures.
What Is Included in the Payment
The calculated monthly payment covers principal and interest only. It does not include property taxes, homeowners insurance, private mortgage insurance (PMI), or HOA fees. These additional costs can significantly increase your actual monthly housing expense and should be estimated separately.
How to Use the Calculator
- Enter the home price – the total purchase price of the property.
- Enter your down payment – either as a dollar amount or a percentage of the home price.
- Enter the annual interest rate – the rate offered by your lender, expressed as a percentage.
- Enter the loan term – typically 15 or 30 years.
- Click calculate to see your estimated monthly payment, total interest, and total loan cost.
Understanding Your Results
The results show three key figures:
- Monthly Payment – the amount you will pay each month for principal and interest.
- Total Interest – the total amount of interest you will pay over the full loan term.
- Total Cost – the sum of your loan amount and total interest, representing the total cost of the mortgage.
These figures assume you make every payment on time and do not make extra payments. Making additional principal payments would reduce total interest and shorten the loan term.
Common Mistakes to Avoid
- Forgetting to include property taxes and insurance. Principal and interest are only part of your monthly housing cost. Taxes, insurance, and PMI can add hundreds of dollars per month.
- Using an inaccurate interest rate. Your actual rate depends on your credit score, loan type, and lender. Use a realistic estimate based on current market rates and your financial profile.
- Ignoring the down payment percentage. A down payment under 20% typically requires PMI, which increases your monthly cost. This calculator does not include PMI.
- Assuming the rate is fixed for the entire term. This calculator is designed for fixed-rate mortgages only. Adjustable-rate mortgages (ARMs) have rates that can change over time.
Limitations of This Calculator
- Does not include property taxes, homeowners insurance, PMI, or HOA fees.
- Assumes a fixed interest rate for the entire loan term.
- Does not account for prepayment penalties or early payoff scenarios.
- Does not consider closing costs or other upfront fees.
- Results are estimates only and should not replace professional financial advice or a formal loan pre-approval.
Practical Use Cases
- Budgeting for a home purchase. Use the calculator to see how different home prices, down payments, and interest rates affect your monthly payment.
- Comparing loan terms. See how a 15-year mortgage compares to a 30-year mortgage in terms of monthly payment and total interest.
- Evaluating the impact of a larger down payment. Increase your down payment to see how it reduces your monthly payment and total interest.
- Planning for refinancing. Estimate how a lower interest rate could reduce your monthly payment and total interest costs.
Frequently Asked Questions
Does this calculator include property taxes and insurance?
No. This calculator estimates principal and interest only. Property taxes, homeowners insurance, and PMI are not included and must be estimated separately to get a complete picture of your monthly housing cost.
What is a good down payment percentage?
A down payment of 20% or more allows you to avoid private mortgage insurance (PMI). However, many lenders offer conventional loans with as little as 3% to 5% down. FHA loans may require as little as 3.5% down. Your ideal down payment depends on your financial situation and loan type.
How does the loan term affect my payment?
A shorter loan term, such as 15 years, results in higher monthly payments but significantly less total interest paid over the life of the loan. A longer term, such as 30 years, lowers your monthly payment but increases total interest costs.
Can I use this calculator for an adjustable-rate mortgage?
This calculator is designed for fixed-rate mortgages only. Adjustable-rate mortgages (ARMs) have interest rates that can change periodically, which this calculator does not account for. Using it for an ARM would give you an estimate based only on the initial rate.
How accurate are the results?
The results are mathematically accurate based on the inputs you provide. However, they are estimates. Your actual mortgage payment will depend on your specific loan terms, interest rate, and additional costs like taxes and insurance. Always consult with a lender for a formal pre-approval and detailed cost breakdown.