Please enter valid numeric values greater than zero.
Principal & Interest:$0.00
Property Tax (Monthly):$0.00
Home Insurance (Monthly):$0.00
HOA Fees:$0.00
Total Monthly Payment:$0.00
Total Interest Paid (Over Term):$0.00
function calculateMortgage() {
// Clear errors
document.getElementById('mgc_error').style.display = 'none';
document.getElementById('mgc-results').style.display = 'none';
// Get Inputs
var price = parseFloat(document.getElementById('mgc_price').value);
var down = parseFloat(document.getElementById('mgc_down').value);
var rate = parseFloat(document.getElementById('mgc_rate').value);
var term = parseFloat(document.getElementById('mgc_term').value);
var taxYear = parseFloat(document.getElementById('mgc_tax').value);
var insYear = parseFloat(document.getElementById('mgc_insurance').value);
var hoaMonth = parseFloat(document.getElementById('mgc_hoa').value);
// Validation
if (isNaN(price) || isNaN(down) || isNaN(rate) || isNaN(term) || isNaN(taxYear) || isNaN(insYear) || price <= 0 || term = price
if (loanAmount <= 0) {
loanAmount = 0;
var monthlyPI = 0;
var totalInterest = 0;
} else {
// Rate conversion
var monthlyRate = (rate / 100) / 12;
var numberOfPayments = term * 12;
// Mortgage Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
if (rate === 0) {
var monthlyPI = loanAmount / numberOfPayments;
} else {
var mathPow = Math.pow(1 + monthlyRate, numberOfPayments);
var monthlyPI = loanAmount * ((monthlyRate * mathPow) / (mathPow – 1));
}
var totalPaymentAmount = monthlyPI * numberOfPayments;
var totalInterest = totalPaymentAmount – loanAmount;
}
var monthlyTax = taxYear / 12;
var monthlyIns = insYear / 12;
var totalMonthly = monthlyPI + monthlyTax + monthlyIns + hoaMonth;
// Formatting currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
// Display Results
document.getElementById('res_principal_interest').innerHTML = formatter.format(monthlyPI);
document.getElementById('res_tax').innerHTML = formatter.format(monthlyTax);
document.getElementById('res_insurance').innerHTML = formatter.format(monthlyIns);
document.getElementById('res_hoa').innerHTML = formatter.format(hoaMonth);
document.getElementById('res_total').innerHTML = formatter.format(totalMonthly);
document.getElementById('res_total_interest').innerHTML = formatter.format(totalInterest);
document.getElementById('mgc-results').style.display = 'block';
}
Understand Your Mortgage Payments
Purchasing a home is likely the largest financial commitment you will make in your lifetime. Understanding exactly where your monthly payments go is crucial for financial planning. This Mortgage Payment Calculator helps you estimate your monthly housing costs by factoring in not just the loan repayment, but also taxes, insurance, and HOA fees.
How to Use This Calculator
To get the most accurate estimate, gather your financial details and input them into the fields above:
Home Price: The total purchase price of the property.
Down Payment: The cash amount you are paying upfront. A higher down payment reduces your loan principal and monthly interest costs.
Interest Rate: The annual percentage rate (APR) quoted by your lender. Even a small difference here can impact your monthly payment significantly.
Loan Term: The duration of the loan. 30 years is standard, but 15-year terms offer lower interest rates and faster equity building.
Property Tax & Insurance: These are often bundled into your monthly payment via an escrow account. Check local tax rates and insurance quotes for accuracy.
Components of Your Monthly Payment
Your "sticker price" for a mortgage often only includes Principal and Interest (P&I). However, the real cost to own (PITI) includes:
Principal: The money that goes towards paying down the loan balance.
Interest: The cost of borrowing money paid to the lender. In the early years of a mortgage, the majority of your payment goes toward interest.
Taxes: Property taxes charged by your local government, usually based on the assessed value of your home.
Insurance: Homeowners insurance protects your property against damage and liability. Lenders require this to protect their investment.
Why Your Interest Rate Matters
Interest rates are determined by the broader economic environment and your personal credit score. On a $300,000 loan, the difference between a 6% and a 7% interest rate might seem small, but it can add hundreds of dollars to your monthly payment and cost tens of thousands in extra interest over the life of the loan. Use the calculator above to compare different rate scenarios before locking in a loan.
Private Mortgage Insurance (PMI)
Note that if your down payment is less than 20% of the home price, lenders may require Private Mortgage Insurance (PMI). While this calculator includes taxes and standard insurance, be aware that PMI can add 0.5% to 1% of the loan amount annually to your costs until you reach 20% equity.