.calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
color: #333;
background: #fff;
padding: 20px;
border-radius: 8px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
.calc-container {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 40px;
border: 1px solid #eee;
padding: 25px;
border-radius: 8px;
background-color: #f9f9f9;
}
.calc-inputs {
flex: 1 1 300px;
}
.calc-results {
flex: 1 1 300px;
background-color: #004d40;
color: white;
padding: 20px;
border-radius: 8px;
display: flex;
flex-direction: column;
justify-content: center;
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
font-size: 14px;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.calc-btn {
width: 100%;
padding: 12px;
background-color: #00796b;
color: white;
border: none;
border-radius: 4px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #004d40;
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 15px;
border-bottom: 1px solid rgba(255,255,255,0.2);
padding-bottom: 10px;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
font-size: 14px;
opacity: 0.9;
}
.result-value {
font-size: 18px;
font-weight: bold;
}
.big-result {
text-align: center;
margin-bottom: 20px;
}
.big-result .amount {
font-size: 36px;
font-weight: bold;
display: block;
margin-top: 5px;
}
.article-content {
line-height: 1.6;
}
.article-content h2 {
color: #004d40;
margin-top: 30px;
}
.article-content p {
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
@media (max-width: 600px) {
.calc-container {
flex-direction: column;
}
}
function calculateMortgage() {
var homePrice = parseFloat(document.getElementById('mc_home_price').value);
var downPayment = parseFloat(document.getElementById('mc_down_payment').value);
var interestRate = parseFloat(document.getElementById('mc_interest_rate').value);
var loanTermYears = parseFloat(document.getElementById('mc_loan_term').value);
var annualTax = parseFloat(document.getElementById('mc_property_tax').value);
var annualInsurance = parseFloat(document.getElementById('mc_home_insurance').value);
// Validation
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(loanTermYears)) {
alert("Please enter valid numbers for all main fields.");
return;
}
// Defaults for optional fields if empty/NaN
if (isNaN(annualTax)) annualTax = 0;
if (isNaN(annualInsurance)) annualInsurance = 0;
var principal = homePrice – downPayment;
var monthlyInterest = (interestRate / 100) / 12;
var numberOfPayments = loanTermYears * 12;
// Principal & Interest Calculation
var monthlyPI = 0;
if (interestRate === 0) {
monthlyPI = principal / numberOfPayments;
} else {
monthlyPI = principal * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments)) / (Math.pow(1 + monthlyInterest, numberOfPayments) – 1);
}
// Tax and Insurance Calculation
var monthlyTax = annualTax / 12;
var monthlyInsurance = annualInsurance / 12;
var totalMonthlyPayment = monthlyPI + monthlyTax + monthlyInsurance;
// Display Results
document.getElementById('mc_total_monthly').innerHTML = "$" + totalMonthlyPayment.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('mc_pi_result').innerHTML = "$" + monthlyPI.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('mc_tax_result').innerHTML = "$" + monthlyTax.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('mc_ins_result').innerHTML = "$" + monthlyInsurance.toLocaleString('en-US', {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('mc_loan_amount_result').innerHTML = "$" + principal.toLocaleString('en-US', {minimumFractionDigits: 0, maximumFractionDigits: 0});
}
// Run calculation on load with default values
window.onload = function() {
calculateMortgage();
};
Mortgage Details
Estimated Monthly Payment
$0.00
Principal & Interest
$0.00
Property Tax
$0.00
Home Insurance
$0.00
Loan Amount
$0.00
Understanding Your Mortgage Payment
Purchasing a home is one of the most significant financial decisions you will make. This Mortgage Payment Calculator is designed to help you understand exactly what your monthly financial commitment will look like. Unlike basic calculators that only show Principal and Interest, this tool includes Property Taxes and Home Insurance estimates to provide a realistic "Out-the-Door" monthly cost (PITI).
Components of a Mortgage Payment (PITI)
When you make a mortgage payment, your money is typically split into four distinct buckets, often referred to by the acronym PITI:
- Principal: This portion of the payment goes directly toward reducing the outstanding balance of your loan. In the early years of a 30-year mortgage, the principal portion is small, but it grows over time.
- Interest: This is the cost of borrowing money. Lenders front-load interest, meaning a large percentage of your early payments pays off interest rather than your loan balance.
- Taxes: Property taxes are assessed by your local government. Lenders typically collect this monthly and hold it in an escrow account to pay the bill when it's due.
- Insurance: Homeowners insurance protects your property against damage. Like taxes, this is often collected monthly into escrow.
How the Mortgage Formula Works
The core calculation for the Principal and Interest (P&I) portion uses the standard amortization formula:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
Where M is the total monthly payment, P is the principal loan amount, i is the monthly interest rate, and n is the number of months required to repay the loan.
Factors Affecting Your Monthly Payment
Several variables can drastically change your monthly affordability:
- Down Payment: putting 20% down eliminates Private Mortgage Insurance (PMI) and lowers the principal amount, reducing both monthly costs and total interest paid over the life of the loan.
- Loan Term: A 15-year term will have higher monthly payments than a 30-year term, but you will pay significantly less in total interest.
- Interest Rate: Even a 1% difference in interest rate can change your monthly payment by hundreds of dollars and your lifetime cost by tens of thousands.
Using This Calculator for Budgeting
Financial experts generally recommend that your total housing costs (mortgage + utilities + maintenance) should not exceed 28% of your gross monthly income. Use the results from the calculator above to ensure your dream home fits within your financial safety zone.