.calc-container {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 20px;
}
.calc-group {
flex: 1;
min-width: 200px;
display: flex;
flex-direction: column;
}
.calc-label {
font-weight: 600;
margin-bottom: 8px;
color: #2c3e50;
font-size: 14px;
}
.calc-input {
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
transition: border-color 0.15s ease-in-out;
}
.calc-input:focus {
border-color: #3498db;
outline: none;
}
.calc-btn {
background-color: #2980b9;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 5px;
cursor: pointer;
width: 100%;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #1c5980;
}
.calc-results {
background-color: #fff;
border: 1px solid #dfe6e9;
border-radius: 6px;
padding: 20px;
margin-top: 25px;
display: none;
}
.result-item {
display: flex;
justify-content: space-between;
align-items: center;
padding: 10px 0;
border-bottom: 1px solid #f1f2f6;
}
.result-item:last-child {
border-bottom: none;
}
.result-label {
color: #7f8c8d;
}
.result-value {
font-weight: 700;
font-size: 18px;
color: #2c3e50;
}
.main-result {
text-align: center;
padding: 15px;
background-color: #e8f6f3;
border-radius: 6px;
margin-bottom: 20px;
}
.main-result h3 {
margin: 0 0 10px 0;
color: #16a085;
font-size: 16px;
text-transform: uppercase;
letter-spacing: 1px;
}
.main-result .big-number {
font-size: 36px;
color: #16a085;
font-weight: 800;
}
.calc-error {
color: #e74c3c;
text-align: center;
margin-top: 10px;
display: none;
}
.seo-content {
line-height: 1.6;
color: #333;
}
.seo-content h2 {
color: #2c3e50;
margin-top: 40px;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
}
.seo-content ul {
margin-bottom: 20px;
}
.seo-content li {
margin-bottom: 10px;
}
function calculateMortgage() {
// 1. Get Input Values
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 errorMsg = document.getElementById('errorMessage');
var resultsArea = document.getElementById('resultsArea');
// 2. Validate Inputs
if (homePrice === "" || downPayment === "" || interestRate === "" || loanTerm === "" || isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTerm)) {
errorMsg.style.display = "block";
resultsArea.style.display = "none";
return;
}
// Convert strings to floats
var P_price = parseFloat(homePrice);
var D_down = parseFloat(downPayment);
var R_annual = parseFloat(interestRate);
var T_years = parseFloat(loanTerm);
// Logic Check: Down payment cannot exceed home price
if (D_down >= P_price) {
errorMsg.innerHTML = "Down payment cannot be equal to or greater than home price.";
errorMsg.style.display = "block";
resultsArea.style.display = "none";
return;
} else {
errorMsg.innerHTML = "Please enter valid numeric values for all fields."; // Reset msg
errorMsg.style.display = "none";
}
// 3. Calculation Logic
// Loan Principal
var Principal = P_price – D_down;
// Monthly Interest Rate (r)
var r = (R_annual / 100) / 12;
// Total Number of Payments (n)
var n = T_years * 12;
var monthlyPayment = 0;
if (R_annual === 0) {
// Handle 0% interest edge case
monthlyPayment = Principal / n;
} else {
// Standard Amortization Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
monthlyPayment = Principal * ( (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) – 1) );
}
var totalPayment = monthlyPayment * n;
var totalInterest = totalPayment – Principal;
// Calculate Payoff Date
var today = new Date();
var payoffDate = new Date(today.setMonth(today.getMonth() + n));
var payoffMonthYear = payoffDate.toLocaleString('default', { month: 'short', year: 'numeric' });
// 4. Formatting Output
function formatCurrency(num) {
return "$" + num.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
}
// 5. Update HTML
document.getElementById('monthlyPaymentDisplay').innerHTML = formatCurrency(monthlyPayment);
document.getElementById('principalDisplay').innerHTML = formatCurrency(Principal);
document.getElementById('totalInterestDisplay').innerHTML = formatCurrency(totalInterest);
document.getElementById('totalCostDisplay').innerHTML = formatCurrency(totalPayment);
document.getElementById('payoffDateDisplay').innerHTML = payoffMonthYear;
// Show results
resultsArea.style.display = "block";
}
Mortgage Payment Calculator
Please enter valid numeric values for all fields.
Estimated Monthly Payment
$0.00
Loan Principal Amount:
$0.00
Total Interest Paid:
$0.00
Total Cost of Loan:
$0.00
Payoff Date:
–
Understanding Your Mortgage Calculation
Calculating your potential mortgage payments is a crucial first step in the home buying process. This Mortgage Payment Calculator helps you estimate your monthly financial commitment based on the home's price, your down payment, the interest rate, and the length of the loan.
Key Factors Affecting Your Mortgage
Several variables influence how much you will pay month-to-month and over the life of your loan:
- Principal: This is the amount of money you borrow. It is calculated as the home price minus your down payment. A larger down payment reduces your principal and, consequently, your monthly payments and total interest.
- Interest Rate: This is the cost of borrowing money, expressed as a percentage. Even a small difference in the interest rate (e.g., 6.0% vs 6.5%) can add up to tens of thousands of dollars over a 30-year term.
- Loan Term: The most common terms are 15 and 30 years. A 30-year loan typically has lower monthly payments but results in higher total interest costs compared to a 15-year loan.
How Amortization Works
Mortgages generally use an amortization schedule. In the early years of your loan, a significant portion of your monthly payment goes toward paying off interest. As time passes, the portion allocated to interest decreases, and more of your payment goes toward reducing the principal balance.
Tips for Lowering Your Mortgage Costs
- Increase Your Down Payment: Putting down 20% or more typically eliminates the need for Private Mortgage Insurance (PMI) and lowers your monthly obligation.
- Improve Your Credit Score: Lenders reserve their best interest rates for borrowers with high credit scores (typically 760 and above).
- Make Extra Payments: Paying just one extra mortgage payment per year can shorten your loan term by years and save you substantial interest.