Buying a home is one of the largest financial decisions you will make. Understanding your estimated monthly mortgage payment is crucial for budgeting and determining how much house you can afford. This calculator breaks down your principal, interest, taxes, and insurance to give you a clear picture of your monthly housing costs.
30 Years
20 Years
15 Years
10 Years
Your Estimated Monthly Payment
$0.00
Principal & Interest$0.00
Property Tax (Monthly)$0.00
Home Insurance (Monthly)$0.00
Total Loan Amount:0.00 |
Total Interest Paid:0.00
Components of Your Mortgage Payment
When you take out a home loan, your monthly payment typically consists of four main parts, often referred to as PITI:
Principal: This is the portion of your payment that goes toward paying down the actual money you borrowed. In the early years of a mortgage, this amount is small compared to the interest.
Interest: This is the cost of borrowing money from the lender. The higher your interest rate, the more you pay over the life of the loan.
Taxes: Property taxes are assessed by your local government. Lenders often collect this monthly and hold it in an escrow account to pay the bill when it's due.
Insurance: Homeowner's insurance protects your property against hazards like fire and theft. Like taxes, this is often paid via escrow.
How Interest Rates Affect Affordability
Even a small difference in interest rates can significantly impact your monthly payment and the total cost of the loan. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly payment by hundreds of dollars and your total interest paid by tens of thousands over 30 years.
Why Calculate Before You Shop?
Using a mortgage calculator helps you set realistic expectations before you start viewing homes. It ensures you focus on properties that fit your monthly budget, factoring in not just the sticker price, but the recurring costs of taxes and insurance specific to that area.
function calculateMortgage() {
// Get Inputs by ID
var homePrice = parseFloat(document.getElementById("mc-home-price").value);
var downPayment = parseFloat(document.getElementById("mc-down-payment").value);
var interestRate = parseFloat(document.getElementById("mc-interest-rate").value);
var loanTermYears = parseInt(document.getElementById("mc-loan-term").value);
var yearlyTax = parseFloat(document.getElementById("mc-property-tax").value);
var yearlyInsurance = parseFloat(document.getElementById("mc-insurance").value);
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTermYears)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (downPayment > homePrice) {
alert("Down payment cannot be greater than the home price.");
return;
}
// Calculations
var loanAmount = homePrice – downPayment;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPrincipalInterest = 0;
// Handle 0% interest edge case
if (interestRate === 0) {
monthlyPrincipalInterest = loanAmount / numberOfPayments;
} else {
// Standard Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
monthlyPrincipalInterest = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
var monthlyTax = yearlyTax / 12;
var monthlyInsurance = yearlyInsurance / 12;
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyInsurance;
var totalCostOfLoan = (monthlyPrincipalInterest * numberOfPayments);
var totalInterest = totalCostOfLoan – loanAmount;
// Display Results
// Helper function for currency formatting
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById("mc-total-monthly").innerText = totalMonthlyPayment.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("mc-pi-result").innerText = formatter.format(monthlyPrincipalInterest);
document.getElementById("mc-tax-result").innerText = formatter.format(monthlyTax);
document.getElementById("mc-ins-result").innerText = formatter.format(monthlyInsurance);
document.getElementById("mc-loan-amount").innerText = formatter.format(loanAmount);
document.getElementById("mc-total-interest").innerText = formatter.format(totalInterest);
// Show the result container
document.getElementById("mc-results").style.display = "block";
}