.seocalc-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
}
.seocalc-box {
background: #ffffff;
padding: 25px;
border-radius: 8px;
box-shadow: 0 2px 5px rgba(0,0,0,0.05);
margin-bottom: 30px;
}
.seocalc-title {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.seocalc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.seocalc-grid {
grid-template-columns: 1fr;
}
}
.seocalc-input-group {
margin-bottom: 15px;
}
.seocalc-label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
color: #444;
}
.seocalc-input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.seocalc-input:focus {
border-color: #0073aa;
outline: none;
}
.seocalc-btn {
grid-column: 1 / -1;
background-color: #0073aa;
color: white;
padding: 12px 20px;
border: none;
border-radius: 4px;
font-size: 16px;
cursor: pointer;
width: 100%;
font-weight: bold;
transition: background 0.3s;
}
.seocalc-btn:hover {
background-color: #005177;
}
.seocalc-results {
margin-top: 25px;
padding-top: 20px;
border-top: 2px solid #f0f0f0;
display: none;
}
.seocalc-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
font-size: 15px;
}
.seocalc-result-row.total {
font-weight: bold;
color: #2c3e50;
font-size: 18px;
margin-top: 15px;
padding-top: 10px;
border-top: 1px dashed #ccc;
}
.seocalc-content {
line-height: 1.6;
color: #333;
}
.seocalc-content h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #0073aa;
padding-bottom: 10px;
display: inline-block;
}
.seocalc-content h3 {
color: #444;
margin-top: 20px;
}
.seocalc-content ul {
margin-bottom: 20px;
}
.error-msg {
color: red;
font-size: 14px;
margin-top: 5px;
display: none;
}
function calculateMortgage() {
// 1. Get DOM elements
var elHomeValue = document.getElementById('homeValue');
var elDownPayment = document.getElementById('downPayment');
var elLoanTerm = document.getElementById('loanTerm');
var elInterestRate = document.getElementById('interestRate');
var elPropertyTax = document.getElementById('propertyTax');
var elInsurance = document.getElementById('insurance');
var elHoaFees = document.getElementById('hoaFees');
var elResultDisplay = document.getElementById('resultDisplay');
var elErrorDisplay = document.getElementById('errorDisplay');
var elResPI = document.getElementById('resPI');
var elResTax = document.getElementById('resTax');
var elResIns = document.getElementById('resIns');
var elResHOA = document.getElementById('resHOA');
var elResTotal = document.getElementById('resTotal');
var elResTotalInterest = document.getElementById('resTotalInterest');
// 2. Parse values
var homeValue = parseFloat(elHomeValue.value);
var downPayment = parseFloat(elDownPayment.value);
var loanTermYears = parseFloat(elLoanTerm.value);
var annualInterestRate = parseFloat(elInterestRate.value);
var annualTax = parseFloat(elPropertyTax.value);
var annualInsurance = parseFloat(elInsurance.value);
var monthlyHOA = parseFloat(elHoaFees.value);
// 3. Validation
if (isNaN(homeValue) || isNaN(downPayment) || isNaN(loanTermYears) ||
isNaN(annualInterestRate) || isNaN(annualTax) || isNaN(annualInsurance) || isNaN(monthlyHOA) ||
homeValue < 0 || downPayment < 0 || loanTermYears home value
if (principal < 0) principal = 0;
var monthlyInterestRate = (annualInterestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
var monthlyPI = 0;
if (annualInterestRate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
// Standard Amortization Formula
var x = Math.pow(1 + monthlyInterestRate, numberOfPayments);
monthlyPI = (principal * x * monthlyInterestRate) / (x – 1);
}
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var totalMonthlyPayment = monthlyPI + monthlyTax + monthlyInsurance + monthlyHOA;
var totalAmountPaid = (monthlyPI * numberOfPayments);
var totalInterest = totalAmountPaid – principal;
// 5. Update UI
// Format to currency
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
elResPI.innerHTML = formatter.format(monthlyPI);
elResTax.innerHTML = formatter.format(monthlyTax);
elResIns.innerHTML = formatter.format(monthlyInsurance);
elResHOA.innerHTML = formatter.format(monthlyHOA);
elResTotal.innerHTML = formatter.format(totalMonthlyPayment);
elResTotalInterest.innerHTML = formatter.format(totalInterest);
elResultDisplay.style.display = 'block';
}
Mortgage Payment Calculator
Please enter valid positive numbers for all fields.
Principal & Interest:
$0.00
Property Tax (Monthly):
$0.00
Home Insurance (Monthly):
$0.00
HOA Fees (Monthly):
$0.00
Total Monthly Payment:
$0.00
Total Interest Paid over Loan Life:
$0.00
How to Use This Mortgage Calculator
Purchasing a home is one of the most significant financial decisions you will make. This Mortgage Calculator is designed to provide a comprehensive breakdown of your potential monthly payments, helping you understand exactly what you can afford. While the mortgage principal and interest usually make up the bulk of your payment, additional costs like property taxes, homeowners insurance, and HOA fees can significantly impact your budget.
To use the calculator effectively, simply enter the current listing price of the home, your planned down payment, the loan term (usually 15 or 30 years), and your expected interest rate. Don't forget to include estimates for taxes and insurance to get the most accurate "out-the-door" monthly cost.
Understanding the Components of Your Payment
Your monthly mortgage payment is typically composed of four main parts, often referred to as PITI (Principal, Interest, Taxes, and Insurance):
- Principal: The portion of your payment that goes toward paying down the loan balance.
- Interest: The cost of borrowing money from your lender. In the early years of a mortgage, a larger percentage of your payment goes toward interest.
- Property Taxes: Taxes charged by your local government based on the value of your property. These are often collected by the lender and held in an escrow account.
- Homeowners Insurance: Protection for your home against damages. Like taxes, this is often paid via escrow.
Mortgage Calculation Formula
This calculator uses the standard amortization formula to determine your monthly Principal and Interest (P&I) payment:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
Where:
- M = Total monthly payment
- P = Principal loan amount (Home Price minus Down Payment)
- i = Monthly interest rate (Annual rate divided by 12)
- n = Number of payments (Loan term in years multiplied by 12)
Example Scenario
For example, if you purchase a home for $350,000 with a $70,000 (20%) down payment, your loan amount is $280,000. If you secure a 30-year fixed-rate mortgage at 6.5% interest:
- Your Principal & Interest payment would be approximately $1,769.
- If Property Taxes are $4,200/year, that adds $350/month.
- If Insurance is $1,200/year, that adds $100/month.
- Total Estimated Payment: ~$2,219/month.