Mortgage Payment Calculator
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Mortgage Payment Calculator
Principal & Interest:
$0.00
Monthly Property Tax:
$0.00
Monthly Insurance:
$0.00
Total Monthly Payment:
$0.00
*Excludes HOA fees and PMI if applicable.
Understanding Your Mortgage Payment
Calculating your monthly mortgage payment is the first critical step in the home buying process. This Mortgage Payment Calculator helps you estimate your monthly financial commitment by factoring in the four key components of PITI: Principal, Interest, Taxes, and Insurance.
Breakdown of Mortgage Costs
When you take out a home loan, your monthly bill covers more than just paying back the money you borrowed. Here is what is included:
- Principal: The portion of the payment that reduces the remaining balance of the loan.
- Interest: The fee charged by the lender for borrowing the money. In the early years of a mortgage, a significant portion of your payment goes toward interest.
- Property Taxes: Taxes assessed by your local government, usually held in escrow by your lender and paid annually on your behalf.
- Homeowners Insurance: Protection for your property against hazards like fire and theft, also typically paid via escrow.
How Interest Rates Affect Affordability
Even a small change in interest rates can significantly impact your monthly payment and the total cost of your loan over time. For example, on a $300,000 loan, a 1% increase in the interest rate can raise your monthly payment by hundreds of dollars. It is essential to shop around for the best rate and improve your credit score before applying.
Choosing the Right Loan Term
While a 30-year fixed-rate mortgage is the most common choice due to lower monthly payments, a 15-year term can save you tens of thousands of dollars in interest over the life of the loan. Use the calculator above to compare how different terms affect your monthly budget.
The Importance of a Down Payment
Your down payment directly reduces the principal amount of your loan. A larger down payment (typically 20% or more) lowers your monthly P&I payment and helps you avoid Private Mortgage Insurance (PMI), an extra cost added to loans with smaller down payments.
function calculateMortgage() {
// 1. Get Input Values
var price = parseFloat(document.getElementById('homePrice').value);
var down = parseFloat(document.getElementById('downPayment').value);
var rate = parseFloat(document.getElementById('interestRate').value);
var termYears = parseInt(document.getElementById('loanTerm').value);
var annualTax = parseFloat(document.getElementById('propertyTax').value);
var annualIns = parseFloat(document.getElementById('homeInsurance').value);
// 2. Validation
if (isNaN(price) || isNaN(down) || isNaN(rate) || isNaN(termYears)) {
alert("Please enter valid numbers for all fields.");
return;
}
if (down >= price) {
alert("Down payment cannot be equal to or greater than the home price.");
return;
}
// 3. Core Calculations
var principal = price – down;
var monthlyRate = rate / 100 / 12;
var numberOfPayments = termYears * 12;
// Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var monthlyPI = 0;
if (rate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
monthlyPI = principal * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
var monthlyTax = annualTax / 12;
var monthlyIns = annualIns / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns;
// 4. Update UI
// Helper function for currency formatting
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
document.getElementById('resPI').innerHTML = formatCurrency(monthlyPI);
document.getElementById('resTax').innerHTML = formatCurrency(monthlyTax);
document.getElementById('resIns').innerHTML = formatCurrency(monthlyIns);
document.getElementById('resTotal').innerHTML = formatCurrency(totalMonthly);
// Show results
document.getElementById('results').style.display = "block";
}