Mortgage Payment Calculator
.mp-calculator-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
border: 1px solid #e2e8f0;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
background: #fff;
}
.mp-calc-header {
background-color: #2c5282;
color: white;
padding: 20px;
border-top-left-radius: 8px;
border-top-right-radius: 8px;
text-align: center;
}
.mp-calc-header h2 {
margin: 0;
font-size: 24px;
}
.mp-calc-body {
padding: 30px;
display: flex;
flex-wrap: wrap;
gap: 30px;
}
.mp-input-section {
flex: 1;
min-width: 300px;
}
.mp-result-section {
flex: 1;
min-width: 300px;
background-color: #f7fafc;
border-radius: 8px;
padding: 20px;
display: flex;
flex-direction: column;
justify-content: center;
}
.mp-form-group {
margin-bottom: 20px;
}
.mp-form-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #4a5568;
font-size: 14px;
}
.mp-input-wrapper {
position: relative;
}
.mp-input-symbol {
position: absolute;
left: 10px;
top: 50%;
transform: translateY(-50%);
color: #a0aec0;
}
.mp-input-symbol-right {
position: absolute;
right: 10px;
top: 50%;
transform: translateY(-50%);
color: #a0aec0;
}
.mp-form-control {
width: 100%;
padding: 10px 10px 10px 30px;
border: 1px solid #cbd5e0;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.2s;
}
.mp-form-control:focus {
outline: none;
border-color: #2c5282;
box-shadow: 0 0 0 3px rgba(44, 82, 130, 0.2);
}
.mp-btn {
width: 100%;
padding: 14px;
background-color: #2c5282;
color: white;
border: none;
border-radius: 6px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
}
.mp-btn:hover {
background-color: #2a4365;
}
.mp-result-box {
text-align: center;
margin-bottom: 20px;
}
.mp-result-label {
font-size: 14px;
color: #718096;
text-transform: uppercase;
letter-spacing: 1px;
margin-bottom: 5px;
}
.mp-result-value {
font-size: 36px;
font-weight: 800;
color: #2c5282;
}
.mp-breakdown {
border-top: 1px solid #e2e8f0;
padding-top: 15px;
margin-top: 15px;
}
.mp-breakdown-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
font-size: 14px;
color: #4a5568;
}
.mp-breakdown-row span:last-child {
font-weight: 600;
}
.mp-content-article {
max-width: 800px;
margin: 40px auto;
line-height: 1.6;
color: #2d3748;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
.mp-content-article h2 {
color: #2c5282;
margin-top: 30px;
font-size: 24px;
}
.mp-content-article h3 {
color: #2d3748;
font-size: 20px;
margin-top: 25px;
}
.mp-content-article p {
margin-bottom: 15px;
}
.mp-content-article ul {
margin-bottom: 15px;
padding-left: 20px;
}
.mp-content-article li {
margin-bottom: 8px;
}
Estimated Monthly Payment
$0.00
Principal & Interest:
$0.00
Property Tax:
$0.00
Home Insurance:
$0.00
PMI (Est.):
$0.00
*Calculations are estimates. Actual payments may vary by lender.
Understanding Your Mortgage Calculation
Buying a home is one of the largest financial decisions you will make. This Mortgage Payment Calculator helps you estimate your monthly financial obligation, breaking down the costs beyond just the loan repayment. To truly understand your mortgage, you need to look at PITI: Principal, Interest, Taxes, and Insurance.
1. Principal and Interest
The core of your mortgage payment is the Principal and Interest (P&I). The principal is the money you borrowed to buy the house, while the interest is the cost of borrowing that money. in the early years of a standard fixed-rate mortgage, the majority of your payment goes toward interest. As time passes, a larger portion shifts toward paying down the principal.
2. Property Taxes and Insurance
Many first-time homebuyers are surprised that their monthly payment is higher than the loan payment alone. Lenders typically collect 1/12th of your annual Property Tax and Homeowners Insurance with every mortgage payment. These funds are held in an escrow account and paid on your behalf when due.
3. Private Mortgage Insurance (PMI)
If your down payment is less than 20% of the home's purchase price, lenders usually require Private Mortgage Insurance (PMI). This protects the lender if you default on the loan. Our calculator automatically estimates PMI if your equity is below 20%, giving you a realistic view of your total monthly cost.
How to Lower Your Monthly Payment
- Increase Down Payment: A larger down payment reduces the loan amount and can eliminate the need for PMI.
- Extend the Loan Term: Choosing a 30-year term over a 15-year term lowers monthly payments, though you will pay more interest over the life of the loan.
- Shop for Lower Rates: Even a 0.5% difference in interest rate can save you hundreds of dollars a month and tens of thousands over the life of the loan.
Calculation Formula
The standard formula used to calculate the monthly principal and interest payment is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]
Where:
- M = Total monthly payment
- P = Principal loan amount
- i = Monthly interest rate (Annual rate / 12)
- n = Number of months (Years * 12)
function calculateMortgage() {
// 1. Get Inputs
var homePrice = parseFloat(document.getElementById("mpHomePrice").value);
var downPayment = parseFloat(document.getElementById("mpDownPayment").value);
var interestRate = parseFloat(document.getElementById("mpInterestRate").value);
var years = parseFloat(document.getElementById("mpLoanTerm").value);
var taxRate = parseFloat(document.getElementById("mpPropertyTax").value);
var insuranceYearly = parseFloat(document.getElementById("mpInsurance").value);
// 2. Validate Inputs
if (isNaN(homePrice) || homePrice <= 0) {
alert("Please enter a valid Home Price.");
return;
}
if (isNaN(downPayment) || downPayment < 0) {
downPayment = 0;
}
if (isNaN(interestRate) || interestRate < 0) {
alert("Please enter a valid Interest Rate.");
return;
}
if (isNaN(years) || years <= 0) {
alert("Please enter a valid Loan Term.");
return;
}
// 3. Core Calculations
var loanAmount = homePrice – downPayment;
// Prevent negative loan amount
if (loanAmount 0 && monthlyRate > 0) {
monthlyPI = loanAmount * (monthlyRate * Math.pow(1 + monthlyRate, numberOfPayments)) / (Math.pow(1 + monthlyRate, numberOfPayments) – 1);
} else if (loanAmount > 0 && monthlyRate === 0) {
monthlyPI = loanAmount / numberOfPayments;
}
// Calculate Taxes (Monthly)
var yearlyTax = (homePrice * (taxRate / 100));
var monthlyTax = yearlyTax / 12;
// Calculate Insurance (Monthly)
var monthlyInsurance = (isNaN(insuranceYearly) ? 0 : insuranceYearly) / 12;
// Calculate PMI
// Rule of thumb: If Down Payment is < 20%, PMI is roughly 0.5% to 1% of loan amount annually.
// We will use 0.5% as a conservative estimate for this calculator.
var monthlyPMI = 0;
var downPaymentPercent = (downPayment / homePrice) * 100;
if (downPaymentPercent 0) {
monthlyPMI = (loanAmount * 0.005) / 12;
}
// Total Monthly Payment
var totalMonthly = monthlyPI + monthlyTax + monthlyInsurance + monthlyPMI;
// 4. Update UI
// Helper to format currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
document.getElementById("mpTotalResult").innerText = formatter.format(totalMonthly);
document.getElementById("mpPIResult").innerText = formatter.format(monthlyPI);
document.getElementById("mpTaxResult").innerText = formatter.format(monthlyTax);
document.getElementById("mpInsResult").innerText = formatter.format(monthlyInsurance);
document.getElementById("mpPMIResult").innerText = formatter.format(monthlyPMI);
}
// Run calculation on load for default values
window.onload = function() {
calculateMortgage();
};