Estimate your monthly payments including principal, interest, taxes, and insurance.
Please enter valid positive numbers for all fields.
Monthly Payment Breakdown
Principal & Interest:$0.00
Property Tax (Monthly):$0.00
Home Insurance (Monthly):$0.00
Total Monthly Payment:$0.00
Loan Summary:
Total Loan Amount: $0.00
Total Interest Paid: $0.00
Payoff Date: Unknown
Understanding Your Mortgage Payment
Buying a home is one of the largest financial decisions you will make. This Mortgage Calculator helps you determine exactly what your monthly obligations will be, beyond just the listing price of the house. Most mortgage payments are comprised of four main components, often referred to as PITI:
Principal: The portion of your payment that reduces the remaining balance of the loan.
Interest: The cost of borrowing the money, paid to the lender.
Taxes: Property taxes assessed by your local government, typically held in an escrow account.
Insurance: Homeowners insurance to protect the property against hazards like fire or theft.
How Interest Rates Affect Your Buying Power
Even a small change in interest rates can significantly impact your monthly payment and the total cost of your loan. For example, on a $300,000 loan, the difference between a 6% and a 7% interest rate can add hundreds of dollars to your monthly bill and tens of thousands over the life of a 30-year loan. Use the calculator above to scenario-test different rates to see what you can comfortably afford.
Short-Term vs. Long-Term Loans
While a 30-year fixed-rate mortgage is the most common, opting for a 15-year term can save you substantial amounts in interest. However, the trade-off is a higher monthly payment.
Many online calculators only show the Principal and Interest. However, lenders look at your total debt-to-income ratio including taxes and insurance. Failing to account for these costs—which can easily range from $300 to over $1,000 per month depending on your location—can lead to "payment shock" when you receive your first bill. Our calculator includes these essential figures to give you a realistic view of homeownership costs.
function calculateMortgage() {
// 1. Get Input Values by ID
var homePrice = parseFloat(document.getElementById("mc_home_price").value);
var downPayment = parseFloat(document.getElementById("mc_down_payment").value);
var annualRate = parseFloat(document.getElementById("mc_interest_rate").value);
var years = parseFloat(document.getElementById("mc_loan_term").value);
var annualTax = parseFloat(document.getElementById("mc_property_tax").value);
var annualIns = parseFloat(document.getElementById("mc_home_insurance").value);
var errorMsg = document.getElementById("mc_error_msg");
var resultsArea = document.getElementById("mc_results_area");
// 2. Validate Inputs
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(annualRate) || isNaN(years) ||
homePrice <= 0 || years <= 0) {
errorMsg.style.display = "block";
resultsArea.style.display = "none";
return;
}
// Reset error message
errorMsg.style.display = "none";
// 3. Perform Calculations
var principal = homePrice – downPayment;
// Handle case where down payment is greater than home price
if (principal < 0) {
principal = 0;
}
var monthlyInterestRate = annualRate / 100 / 12;
var numberOfPayments = years * 12;
var monthlyPrincipalInterest = 0;
// Amortization Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
if (annualRate === 0) {
monthlyPrincipalInterest = principal / numberOfPayments;
} else {
var mathPower = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPrincipalInterest = principal * (monthlyInterestRate * mathPower) / (mathPower – 1);
}
var monthlyTax = 0;
if (!isNaN(annualTax)) {
monthlyTax = annualTax / 12;
}
var monthlyIns = 0;
if (!isNaN(annualIns)) {
monthlyIns = annualIns / 12;
}
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyIns;
var totalCostOfLoan = (monthlyPrincipalInterest * numberOfPayments);
var totalInterest = totalCostOfLoan – principal;
// Calculate Payoff Date
var today = new Date();
var payoffDate = new Date(today.setMonth(today.getMonth() + numberOfPayments));
var options = { month: 'long', year: 'numeric' };
var payoffString = payoffDate.toLocaleDateString('en-US', options);
// 4. Update UI with Results
// Helper for currency formatting
var currencyFormat = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById("res_pi").innerHTML = currencyFormat.format(monthlyPrincipalInterest);
document.getElementById("res_tax").innerHTML = currencyFormat.format(monthlyTax);
document.getElementById("res_ins").innerHTML = currencyFormat.format(monthlyIns);
document.getElementById("res_total").innerHTML = currencyFormat.format(totalMonthlyPayment);
document.getElementById("res_loan_amount").innerHTML = currencyFormat.format(principal);
document.getElementById("res_total_interest").innerHTML = currencyFormat.format(totalInterest);
document.getElementById("res_payoff_date").innerHTML = payoffString;
// Show Results
resultsArea.style.display = "block";
}