Estimate your monthly payments and total interest costs.
Please enter valid numeric values for all fields.
Monthly Principal & Interest:–
Monthly Tax & Insurance:–
Monthly HOA:–
TOTAL MONTHLY PAYMENT:–
Total Loan Amount:–
Total Interest Paid:–
Total Cost of Loan:–
Understanding Your Mortgage Calculation
Using a comprehensive Mortgage Payment Calculator is the first essential step in the home buying process. It helps prospective homeowners understand exactly how much "house" they can afford by breaking down the monthly financial commitment into its core components.
Components of Your Monthly Payment
Most first-time buyers focus solely on the principal and interest, but your actual monthly check to the bank often includes more. This calculator considers the full PITI + HOA structure:
Principal: The portion of your payment that reduces the loan balance.
Interest: The cost of borrowing money, calculated based on your interest rate and remaining principal.
Taxes: Property taxes are usually collected by the lender in an escrow account and paid to the county annually.
Insurance: Homeowners insurance protects your property and is typically required by lenders.
HOA Fees: If you buy a condo or a home in a planned community, these fees are paid separately but affect your affordability.
How Interest Rates Affect Your Buying Power
Even a small fluctuation in interest rates can significantly impact your monthly payment and the total cost of the loan. For example, on a $300,000 loan, a difference of just 1% in the interest rate can change your monthly payment by hundreds of dollars and your total interest paid over 30 years by tens of thousands.
30-Year vs. 15-Year Term
Choosing your loan term is a balancing act between monthly affordability and long-term savings. A 30-year mortgage offers lower monthly payments, making expensive homes more accessible, but you will pay significantly more in interest over the life of the loan. A 15-year mortgage has higher monthly payments but builds equity faster and saves massive amounts on interest.
Tips for Lowering Your Mortgage Payment
If the calculated payment is higher than your budget allows, consider these strategies:
Increase your down payment: This reduces the principal loan amount and may eliminate Private Mortgage Insurance (PMI).
Improve your credit score: A higher score often qualifies you for a lower interest rate.
Shop for cheaper insurance: Compare quotes to lower the escrow portion of your payment.
Consider points: You can pay "discount points" upfront to lower the interest rate for the life of the loan.
function calculateMortgage() {
// Get input elements
var priceInput = document.getElementById("homePrice");
var downInput = document.getElementById("downPayment");
var rateInput = document.getElementById("interestRate");
var termInput = document.getElementById("loanTerm");
var taxInput = document.getElementById("propertyTax");
var insuranceInput = document.getElementById("insurance");
var hoaInput = document.getElementById("hoaFees");
var resultBox = document.getElementById("resultContainer");
var errorBox = document.getElementById("errorMsg");
// Parse values
var price = parseFloat(priceInput.value);
var down = parseFloat(downInput.value);
var rate = parseFloat(rateInput.value);
var years = parseFloat(termInput.value);
var taxYearly = parseFloat(taxInput.value);
var insuranceYearly = parseFloat(insuranceInput.value);
var hoaMonthly = parseFloat(hoaInput.value);
// Validation
if (isNaN(price) || isNaN(down) || isNaN(rate) || isNaN(years) ||
price <= 0 || years = price
if (loanAmount <= 0) {
loanAmount = 0;
var monthlyPI = 0;
var totalInterest = 0;
var totalCost = 0;
} else {
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = years * 12;
// Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
var monthlyPI = 0;
if (rate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
var totalCostOfLoan = (monthlyPI * numberOfPayments);
var totalInterest = totalCostOfLoan – loanAmount;
}
// Escrow and Extras
var monthlyTax = isNaN(taxYearly) ? 0 : taxYearly / 12;
var monthlyInsurance = isNaN(insuranceYearly) ? 0 : insuranceYearly / 12;
var monthlyHOAVal = isNaN(hoaMonthly) ? 0 : hoaMonthly;
var totalMonthlyPayment = monthlyPI + monthlyTax + monthlyInsurance + monthlyHOAVal;
var totalCostWithExtras = (totalMonthlyPayment * (years * 12)) + down; // Rough estimate of total out of pocket over life
// Format Currency Function
function formatMoney(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// Update UI
document.getElementById("resPI").innerHTML = formatMoney(monthlyPI);
document.getElementById("resEscrow").innerHTML = formatMoney(monthlyTax + monthlyInsurance);
document.getElementById("resHOA").innerHTML = formatMoney(monthlyHOAVal);
document.getElementById("resTotal").innerHTML = formatMoney(totalMonthlyPayment);
document.getElementById("resLoanAmount").innerHTML = formatMoney(loanAmount);
document.getElementById("resTotalInterest").innerHTML = formatMoney(totalInterest);
document.getElementById("resTotalCost").innerHTML = formatMoney(loanAmount + totalInterest); // Principal + Interest only
resultBox.style.display = "block";
}