Please enter valid positive numbers for all fields.
Est. Monthly Payment–
Principal & Interest–
Property Tax (Monthly)–
Home Insurance (Monthly)–
HOA Fees–
Total Loan Amount–
Total Interest Paid–
Payoff Date–
function calculateMortgage() {
var price = parseFloat(document.getElementById('mc_home_price').value);
var down = parseFloat(document.getElementById('mc_down_payment').value);
var rate = parseFloat(document.getElementById('mc_interest_rate').value);
var term = parseFloat(document.getElementById('mc_loan_term').value);
var taxYear = parseFloat(document.getElementById('mc_property_tax').value);
var insYear = parseFloat(document.getElementById('mc_insurance').value);
var hoa = parseFloat(document.getElementById('mc_hoa').value);
// Validation
if (isNaN(price) || isNaN(down) || isNaN(rate) || isNaN(term) || isNaN(taxYear) || isNaN(insYear)) {
document.getElementById('mc_error').style.display = 'block';
document.getElementById('mc-results').style.display = 'none';
return;
}
// Handle HOA defaulting to 0 if empty but not NaN (parsefloat handles empty as NaN usually, so let's fix empty inputs)
if (isNaN(hoa)) hoa = 0;
document.getElementById('mc_error').style.display = 'none';
// Calculations
var loanAmount = price – down;
// Handle full cash purchase
if (loanAmount <= 0) {
loanAmount = 0;
var monthlyPI = 0;
var totalInterest = 0;
} else {
var monthlyRate = rate / 100 / 12;
var totalPayments = term * 12;
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var mathPow = Math.pow(1 + monthlyRate, totalPayments);
var monthlyPI = loanAmount * (monthlyRate * mathPow) / (mathPow – 1);
var totalCost = monthlyPI * totalPayments;
var totalInterest = totalCost – loanAmount;
}
var monthlyTax = taxYear / 12;
var monthlyIns = insYear / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns + hoa;
// Date Calculation
var today = new Date();
var payoffDate = new Date(today.setMonth(today.getMonth() + (term * 12)));
var monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
var dateString = monthNames[payoffDate.getMonth()] + " " + payoffDate.getFullYear();
// Display Results
document.getElementById('res_total_monthly').innerHTML = "$" + totalMonthly.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_pi').innerHTML = "$" + monthlyPI.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_tax').innerHTML = "$" + monthlyTax.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_ins').innerHTML = "$" + monthlyIns.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_hoa').innerHTML = "$" + hoa.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_loan_amount').innerHTML = "$" + loanAmount.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_total_interest').innerHTML = "$" + totalInterest.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
document.getElementById('res_payoff_date').innerHTML = dateString;
document.getElementById('mc-results').style.display = 'block';
}
How to Use This Mortgage Calculator
Purchasing a home is likely the biggest financial decision of your life. Our specific Mortgage Payment Calculator helps you estimate your monthly financial commitment by accounting for all the major costs: principal, interest, taxes, insurance, and HOA fees (PITI).
To get the most accurate result, gather your current home price estimates, available down payment, and expected interest rate. Don't forget to include estimates for annual property taxes and homeowners insurance, as these significantly impact your total monthly outflow.
Understanding Your Monthly Payment Breakdown
Your monthly check to the bank is often split into four or five different buckets. Understanding these helps you budget effectively:
1. Principal and Interest (P&I)
This is the core of your loan. Principal pays down the debt balance, while Interest is the cost of borrowing money. In the early years of a 30-year term, the majority of this portion goes toward interest, gradually shifting toward principal over time.
2. Property Taxes
Local governments assess property taxes to fund schools and services. These are typically paid annually, but lenders often collect 1/12th of the estimated amount each month and hold it in an escrow account to pay the bill for you.
3. Homeowners Insurance
Lenders require insurance to protect the asset against fire, storms, and other damages. Like taxes, this is usually broken down into monthly payments and paid via escrow.
4. HOA Fees
If you are buying a condo or a home in a planned community, you may owe Homeowners Association (HOA) dues. While these are rarely paid through the lender, they are a critical monthly expense that affects your Debt-to-Income (DTI) ratio.
How Interest Rates Affect Your Buying Power
Even a small fluctuation in interest rates can dramatically change your monthly payment. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly payment by hundreds of dollars. Use the "Interest Rate" field in the calculator above to see how different rates impact your budget and total interest paid over the life of the loan.