Please enter valid numerical values greater than zero.
30 Years
20 Years
15 Years
10 Years
Monthly Payment Breakdown
Principal & Interest:$0.00
Property Tax:$0.00
Home Insurance:$0.00
PMI (Estimated):$0.00
Total Monthly Payment:$0.00
*PMI is estimated based on < 20% down payment.
function calculateMortgage() {
// Get input values
var homePrice = parseFloat(document.getElementById("homePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var annualRate = parseFloat(document.getElementById("interestRate").value);
var years = parseInt(document.getElementById("loanTerm").value);
var yearlyTax = parseFloat(document.getElementById("propertyTax").value);
var yearlyIns = parseFloat(document.getElementById("homeInsurance").value);
// Error element
var errorDiv = document.getElementById("calcError");
var resultDiv = document.getElementById("resultsArea");
// Basic Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualRate) || isNaN(years) || homePrice <= 0) {
errorDiv.style.display = "block";
resultDiv.style.display = "none";
return;
} else {
errorDiv.style.display = "none";
}
// Default optional fields to 0 if empty
if (isNaN(yearlyTax)) yearlyTax = 0;
if (isNaN(yearlyIns)) yearlyIns = 0;
// Calculations
var loanAmount = homePrice – downPayment;
// If down payment is greater than home price
if (loanAmount 80%. Avg rate approx 0.5% – 1% of loan amount annually. Using 0.5% as conservative estimate.
var monthlyPMI = 0;
var ltv = (loanAmount / homePrice) * 100;
if (ltv > 80 && loanAmount > 0) {
// Approximate PMI at 0.5% of loan amount annually
monthlyPMI = (loanAmount * 0.005) / 12;
}
var totalMonthly = monthlyPrincipalInterest + monthlyTax + monthlyIns + monthlyPMI;
// Display Results
// Helper function for currency
var fmt = new Intl.NumberFormat('en-US', { style: 'currency', currency: 'USD' });
document.getElementById("resPI").innerText = fmt.format(monthlyPrincipalInterest);
document.getElementById("resTax").innerText = fmt.format(monthlyTax);
document.getElementById("resIns").innerText = fmt.format(monthlyIns);
document.getElementById("resPMI").innerText = fmt.format(monthlyPMI);
document.getElementById("resTotal").innerText = fmt.format(totalMonthly);
resultDiv.style.display = "block";
}
Understanding Your Monthly Mortgage Payment
Buying a home is one of the largest financial decisions you will make. While the home price is the headline number, your monthly obligation is what affects your day-to-day budget. This Mortgage Calculator helps you break down the true cost of homeownership, commonly referred to as PITI: Principal, Interest, Taxes, and Insurance.
What is Included in Your Mortgage Payment?
Most first-time homebuyers are surprised to learn that their check to the bank covers more than just the loan repayment. Here is a breakdown of the components calculated above:
Principal: The portion of your payment that pays down the actual loan balance. In the early years of a 30-year mortgage, this amount is small compared to interest.
Interest: The cost of borrowing money. With a fixed-rate mortgage, the interest rate remains the same, but the amount of interest paid decreases over time as the principal balance shrinks.
Property Taxes: Assessed by your local government to fund schools and public services. This is usually held in escrow by your lender and paid annually on your behalf.
Homeowners Insurance: Protects your property against damage. Like taxes, this is often bundled into your monthly payment via an escrow account.
PMI (Private Mortgage Insurance): If your down payment is less than 20% of the home's value, lenders typically require PMI to protect them against default. This calculator automatically estimates PMI if your loan-to-value ratio exceeds 80%.
How Interest Rates Affect Your Buying Power
Even a small change in interest rates can significantly impact your monthly payment and the total interest paid over the life of the loan. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly payment by approximately $180 to $200. Using this calculator allows you to stress-test your budget against rising rates.
Tips for Lowering Your Monthly Payment
If the total monthly payment calculated above is higher than your budget allows, consider these strategies:
Increase Your Down Payment: Putting more money down reduces the principal loan amount and may eliminate the need for PMI.
Extend the Loan Term: Switching from a 15-year to a 30-year term lowers monthly payments, though you will pay more in total interest over the long run.
Shop for Lower Insurance Rates: Homeowners insurance premiums vary wildly between providers. Shopping around can save you hundreds per year.
Conclusion
Use this tool not just once, but throughout your home buying journey. As you look at different properties with varying tax rates or HOA fees (which should be added to your budget manually), re-run the numbers to ensure you remain financially comfortable.