.calculator-widget {
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 30px;
background-color: #f9f9f9;
border-radius: 12px;
box-shadow: 0 4px 15px rgba(0,0,0,0.05);
border: 1px solid #e0e0e0;
}
.calculator-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 28px;
font-weight: 700;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 8px;
color: #555;
font-weight: 600;
font-size: 14px;
}
.input-wrapper {
position: relative;
}
.input-wrapper input, .input-wrapper select {
width: 100%;
padding: 12px 12px 12px 35px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.3s;
}
.input-wrapper input:focus, .input-wrapper select:focus {
border-color: #3498db;
outline: none;
}
.currency-symbol, .percent-symbol {
position: absolute;
left: 12px;
top: 50%;
transform: translateY(-50%);
color: #777;
}
.percent-symbol {
left: auto;
right: 12px;
}
.calc-btn-container {
grid-column: 1 / -1;
text-align: center;
margin-top: 10px;
}
.calc-btn {
background-color: #27ae60;
color: white;
border: none;
padding: 15px 40px;
font-size: 18px;
font-weight: bold;
border-radius: 8px;
cursor: pointer;
transition: background-color 0.2s;
width: 100%;
}
.calc-btn:hover {
background-color: #219150;
}
.results-container {
grid-column: 1 / -1;
background-color: #fff;
padding: 25px;
border-radius: 8px;
border: 1px solid #eee;
margin-top: 20px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 12px;
padding-bottom: 12px;
border-bottom: 1px solid #f0f0f0;
}
.result-row.total {
border-bottom: none;
margin-top: 15px;
padding-top: 5px;
font-size: 20px;
font-weight: bold;
color: #2c3e50;
}
.result-label {
color: #7f8c8d;
}
.result-value {
font-weight: 600;
color: #2c3e50;
}
.error-msg {
color: #e74c3c;
text-align: center;
grid-column: 1 / -1;
display: none;
margin-top: 10px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
/* Article Styling */
.content-article {
max-width: 800px;
margin: 40px auto;
font-family: 'Segoe UI', Roboto, sans-serif;
line-height: 1.6;
color: #333;
}
.content-article h2 {
color: #2c3e50;
margin-top: 30px;
font-size: 24px;
}
.content-article p {
margin-bottom: 15px;
}
.content-article ul {
margin-bottom: 20px;
padding-left: 20px;
}
.content-article li {
margin-bottom: 8px;
}
function calculateMortgage() {
// Get input values
var homePrice = parseFloat(document.getElementById('homePrice').value);
var downPayment = parseFloat(document.getElementById('downPayment').value);
var interestRate = parseFloat(document.getElementById('interestRate').value);
var loanTermYears = parseInt(document.getElementById('loanTerm').value);
var propertyTaxYearly = parseFloat(document.getElementById('propertyTax').value);
var homeInsuranceYearly = parseFloat(document.getElementById('homeInsurance').value);
// Validation
var errorDiv = document.getElementById('errorMsg');
var resultsDiv = document.getElementById('results');
if (isNaN(homePrice) || isNaN(downPayment) || isNaN(interestRate) || isNaN(propertyTaxYearly) || isNaN(homeInsuranceYearly)) {
errorDiv.style.display = 'block';
resultsDiv.style.display = 'none';
return;
}
if (homePrice <= 0 || downPayment < 0 || interestRate < 0) {
errorDiv.style.display = 'block';
resultsDiv.style.display = 'none';
return;
}
errorDiv.style.display = 'none';
// Calculations
var loanAmount = homePrice – downPayment;
var monthlyInterestRate = (interestRate / 100) / 12;
var totalPayments = loanTermYears * 12;
// Principal & Interest Calculation
var monthlyPrincipalInterest = 0;
if (interestRate === 0) {
monthlyPrincipalInterest = loanAmount / totalPayments;
} else {
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var mathPower = Math.pow(1 + monthlyInterestRate, totalPayments);
monthlyPrincipalInterest = loanAmount * (monthlyInterestRate * mathPower) / (mathPower – 1);
}
// Tax and Insurance
var monthlyTax = propertyTaxYearly / 12;
var monthlyInsurance = homeInsuranceYearly / 12;
var totalMonthlyPayment = monthlyPrincipalInterest + monthlyTax + monthlyInsurance;
var totalCostOfLoan = (monthlyPrincipalInterest * totalPayments);
var totalInterestPaid = totalCostOfLoan – loanAmount;
// Formatter
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
// Update DOM
document.getElementById('resPrincipalInterest').innerText = formatter.format(monthlyPrincipalInterest);
document.getElementById('resTax').innerText = formatter.format(monthlyTax);
document.getElementById('resInsurance').innerText = formatter.format(monthlyInsurance);
document.getElementById('resTotal').innerText = formatter.format(totalMonthlyPayment);
document.getElementById('resTotalInterest').innerText = formatter.format(totalInterestPaid);
resultsDiv.style.display = 'block';
}
Understanding Your Mortgage Calculation
Buying a home is likely the largest financial commitment you will make in your lifetime. Understanding how your monthly mortgage payment is calculated is essential for budgeting and long-term financial planning. This calculator helps break down the complex variables involved in a home loan, giving you a clear picture of what you can afford.
The Components of Your Monthly Payment
Many first-time homebuyers focus solely on the loan principal and interest, but the actual monthly obligation is often referred to as "PITI": Principal, Interest, Taxes, and Insurance.
- Principal: The portion of your payment that goes toward paying down the loan balance (the home price minus your down payment).
- Interest: The fee charged by the lender for borrowing the money. In the early years of a mortgage, a large percentage of your payment goes toward interest rather than principal.
- Property Taxes: Taxes assessed by your local government, usually based on the value of your property. These are often collected by the lender and held in escrow to be paid annually.
- Homeowners Insurance: Insurance that protects your home against damages. Like taxes, this is often paid monthly into an escrow account.
How Interest Rates Affect Affordability
Even a small fluctuation in interest rates can significantly impact your monthly payment and the total interest paid over the life of the loan. For example, on a $300,000 loan, a 1% increase in interest rate can increase your monthly payment by hundreds of dollars and your total interest paid by tens of thousands over 30 years. Using the calculator above, try adjusting the interest rate field to see how sensitive your payment is to rate changes.
Choosing the Right Loan Term
The loan term determines how long you have to repay the loan. The most common terms are 15 and 30 years.
- 30-Year Fixed: Offers lower monthly payments because the repayment is spread over a longer period. However, you will pay significantly more in total interest.
- 15-Year Fixed: Comes with higher monthly payments, but you build equity faster and pay much less in total interest.
Use the dropdown menu in the calculator to compare how a 15-year term versus a 30-year term changes your financial outlook. While the monthly cost is higher for a shorter term, the long-term savings can be substantial.