Please enter valid positive numbers for Home Price and Interest Rate.
Estimated Monthly Payment
Total Monthly Payment:
$0.00
Principal & Interest:
$0.00
Property Tax (Monthly):
$0.00
Homeowners Insurance (Monthly):
$0.00
HOA Fees:
$0.00
Loan Amount:
$0.00
How to Calculate Your Mortgage Payment
Understanding your monthly mortgage payment is the first critical step in the home buying process. While the purchase price of a home gives you a general idea of cost, the actual monthly cash flow required involves several components commonly referred to as PITI (Principal, Interest, Taxes, and Insurance).
The Components of a Mortgage Payment
This calculator breaks down your payment into four distinct parts to give you a realistic view of your housing costs:
Principal: The portion of your payment that goes directly towards paying down the loan balance.
Interest: The cost of borrowing money, paid to the lender. 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 an escrow account by your lender and paid annually.
Homeowners Insurance: Protection for your property against damage, also typically paid via escrow.
HOA Fees: If you buy a condo or a home in a planned community, you may pay monthly Homeowners Association fees separately or through escrow.
How Interest Rates Affect Your Payment
Even a small change in interest rates can drastically alter your monthly obligation. For example, on a $300,000 loan:
At 6.0% interest, the Principal & Interest payment is roughly $1,799.
At 7.0% interest, the Principal & Interest payment jumps to roughly $1,996.
That is nearly a $200 difference per month solely due to a 1% rate increase, costing tens of thousands of dollars over the life of the loan.
What is an Amortization Schedule?
Mortgages generally use an amortization schedule. This means that while your total monthly Principal & Interest payment remains constant (for fixed-rate loans), the ratio changes over time. In the beginning, you pay mostly interest. Near the end of the loan term, you pay mostly principal. This calculator helps you see the "Total Monthly Payment" snapshot to assist in your budgeting.
Tips for Lowering Your Monthly Payment
If the calculated payment is higher than your budget allows, consider these strategies:
Increase your down payment: This lowers the principal loan amount and may remove the need for Private Mortgage Insurance (PMI).
Shop for lower insurance rates: Homeowners insurance premiums vary significantly between providers.
Look for lower taxes: Property taxes vary by county and district; buying slightly outside a high-tax zone can save hundreds a month.
Buy down the rate: You can sometimes pay "points" upfront to lower the interest rate for the life of the loan.
function calculateMortgage() {
// 1. Get Inputs
var homePrice = document.getElementById('homePrice').value;
var downPayment = document.getElementById('downPayment').value;
var interestRate = document.getElementById('interestRate').value;
var loanTerm = document.getElementById('loanTerm').value;
var propertyTax = document.getElementById('propertyTax').value;
var homeInsurance = document.getElementById('homeInsurance').value;
var hoaFees = document.getElementById('hoaFees').value;
// 2. Validate Inputs
if (homePrice === "" || interestRate === "" || isNaN(homePrice) || isNaN(interestRate)) {
document.getElementById('errorMsg').style.display = 'block';
document.getElementById('resultsSection').style.display = 'none';
return;
} else {
document.getElementById('errorMsg').style.display = 'none';
}
// Parse values to floats
var P = parseFloat(homePrice);
var D = parseFloat(downPayment) || 0;
var r = parseFloat(interestRate);
var t = parseFloat(loanTerm); // years
var taxYear = parseFloat(propertyTax) || 0;
var insYear = parseFloat(homeInsurance) || 0;
var hoaMonth = parseFloat(hoaFees) || 0;
// 3. Calculation Logic
var loanAmount = P – D;
// Prevent negative loan amount
if (loanAmount < 0) {
loanAmount = 0;
}
// Monthly Interest Rate
var monthlyRate = (r / 100) / 12;
// Total Number of Payments
var numberOfPayments = t * 12;
// Calculate Principal & Interest (Standard Mortgage Formula)
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var principalInterest = 0;
if (r === 0) {
// Edge case for 0% interest
principalInterest = loanAmount / numberOfPayments;
} else {
var mathPower = Math.pow(1 + monthlyRate, numberOfPayments);
principalInterest = loanAmount * ((monthlyRate * mathPower) / (mathPower – 1));
}
// Monthly Tax and Insurance
var monthlyTax = taxYear / 12;
var monthlyIns = insYear / 12;
// Total Monthly Payment
var totalMonthly = principalInterest + monthlyTax + monthlyIns + hoaMonth;
// 4. Update UI
// Helper to format currency
function formatMoney(num) {
return "$" + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}
document.getElementById('totalMonthlyPayment').innerHTML = formatMoney(totalMonthly);
document.getElementById('piPayment').innerHTML = formatMoney(principalInterest);
document.getElementById('taxPayment').innerHTML = formatMoney(monthlyTax);
document.getElementById('insPayment').innerHTML = formatMoney(monthlyIns);
document.getElementById('hoaPayment').innerHTML = formatMoney(hoaMonth);
document.getElementById('loanAmountResult').innerHTML = formatMoney(loanAmount);
// Show results
document.getElementById('resultsSection').style.display = 'block';
}