Estimate your monthly payments, including taxes and insurance.
30 Years
20 Years
15 Years
10 Years
Monthly Payment Breakdown
Principal & Interest:–
Property Taxes:–
Home Insurance:–
PMI (Est.):–
Total Monthly Payment:–
Loan Summary
Total Loan Amount:–
Total Interest Paid:–
Payoff Date:–
Understanding Your Mortgage Calculation
Buying a home is one of the largest financial decisions most people make. Using a mortgage calculator is an essential step in determining affordability. This tool helps you break down the monthly costs associated with owning a property, going beyond just the sticker price of the house.
Components of a Monthly Mortgage Payment
Your monthly payment is typically composed of four main parts, often referred to as PITI:
Principal: The portion of your payment that goes toward paying down the loan balance.
Interest: The cost of borrowing money from the lender.
Taxes: Property taxes assessed by your local government, usually held in an escrow account.
Insurance: Homeowners insurance to protect your property against damage, also often paid via escrow.
How Interest Rates Affect Your Payment
Even a small difference in interest rates can significantly impact your monthly payment and the total amount you pay over the life of the loan. For example, on a $300,000 loan, a difference of 1% in the interest rate can change your monthly payment by hundreds of dollars and your total interest paid by tens of thousands.
What is PMI?
Private Mortgage Insurance (PMI) is usually required if your down payment is less than 20% of the home's value. This insurance protects the lender if you stop making payments. Our calculator estimates PMI automatically if your down payment falls below this threshold, giving you a more realistic view of your monthly obligation.
Using This Calculator for Budgeting
To get the most accurate result, try to input exact figures for property taxes and insurance quotes if you have them. If not, the default averages provided (1.2% for tax and typical insurance premiums) serve as a solid baseline for estimation. Experiment with different down payment amounts to see how they influence your monthly cash flow.
function calculateMortgage() {
// Get Input Values
var homePrice = parseFloat(document.getElementById('cal_homePrice').value);
var downPayment = parseFloat(document.getElementById('cal_downPayment').value);
var interestRate = parseFloat(document.getElementById('cal_interestRate').value);
var years = parseInt(document.getElementById('cal_loanTerm').value);
var propertyTaxRate = parseFloat(document.getElementById('cal_propertyTax').value);
var annualInsurance = parseFloat(document.getElementById('cal_homeInsurance').value);
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(years) || isNaN(propertyTaxRate) || isNaN(annualInsurance)) {
alert("Please ensure all fields contain valid numbers.");
return;
}
if (downPayment >= homePrice) {
alert("Down payment cannot be equal to or greater than the home price.");
return;
}
// Calculations
var loanAmount = homePrice – downPayment;
var monthlyRate = (interestRate / 100) / 12;
var numberOfPayments = years * 12;
// Principal & Interest Formula
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
} else {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
}
// Taxes and Insurance
var monthlyTax = (homePrice * (propertyTaxRate / 100)) / 12;
var monthlyInsurance = annualInsurance / 12;
// PMI Calculation (Estimating 0.5% of loan amount annually if LTV > 80%)
var monthlyPMI = 0;
var ltv = (loanAmount / homePrice) * 100;
if (ltv > 80) {
monthlyPMI = (loanAmount * 0.005) / 12;
}
// Totals
var totalMonthly = monthlyPI + monthlyTax + monthlyInsurance + monthlyPMI;
var totalInterest = (monthlyPI * numberOfPayments) – loanAmount;
// Payoff Date
var today = new Date();
today.setFullYear(today.getFullYear() + years);
var payoffMonth = today.toLocaleString('default', { month: 'short' });
var payoffYear = today.getFullYear();
var payoffDateStr = payoffMonth + " " + payoffYear;
// Formatting Helper
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// Update DOM
document.getElementById('res_pi').innerHTML = formatCurrency(monthlyPI);
document.getElementById('res_tax').innerHTML = formatCurrency(monthlyTax);
document.getElementById('res_ins').innerHTML = formatCurrency(monthlyInsurance);
document.getElementById('res_pmi').innerHTML = formatCurrency(monthlyPMI);
document.getElementById('res_total').innerHTML = formatCurrency(totalMonthly);
document.getElementById('res_loanAmount').innerHTML = formatCurrency(loanAmount);
document.getElementById('res_totalInterest').innerHTML = formatCurrency(totalInterest);
document.getElementById('res_payoffDate').innerHTML = payoffDateStr;
// Show Results
document.getElementById('cal_result').style.display = 'block';
}