.calculator-widget-container {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
padding: 20px;
background: #ffffff;
border: 1px solid #e0e0e0;
border-radius: 8px;
}
.calc-input-group {
margin-bottom: 20px;
}
.calc-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #333;
}
.calc-input-group input, .calc-input-group select {
width: 100%;
padding: 12px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.calc-btn {
background-color: #0073aa;
color: white;
border: none;
padding: 15px 30px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #005177;
}
.calc-results {
margin-top: 30px;
padding: 20px;
background-color: #f8f9fa;
border-radius: 4px;
border-left: 5px solid #0073aa;
display: none;
}
.calc-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
font-size: 16px;
}
.calc-result-highlight {
font-size: 24px;
font-weight: bold;
color: #0073aa;
text-align: center;
margin: 15px 0;
}
.calc-article {
margin-top: 50px;
line-height: 1.6;
color: #444;
}
.calc-article h2 {
color: #2c3e50;
margin-top: 30px;
}
.calc-article p {
margin-bottom: 15px;
}
.error-msg {
color: red;
font-size: 14px;
margin-top: 5px;
display: none;
}
{
"@context": "https://schema.org",
"@type": "FAQPage",
"mainEntity": [{
"@type": "Question",
"name": "How is a mortgage payment calculated?",
"acceptedAnswer": {
"@type": "Answer",
"text": "Mortgage payments are calculated using an amortization formula that factors in the principal loan amount, the monthly interest rate, and the total number of months in the loan term."
}
}, {
"@type": "Question",
"name": "Does this calculator include property taxes?",
"acceptedAnswer": {
"@type": "Answer",
"text": "No, this calculator computes principal and interest only. Property taxes, homeowners insurance, and HOA fees vary by location and should be added separately to your budget."
}
}]
}
function calculateMortgage() {
// Get Input Elements
var homePriceInput = document.getElementById("homePrice");
var downPaymentInput = document.getElementById("downPayment");
var interestRateInput = document.getElementById("interestRate");
var loanTermInput = document.getElementById("loanTerm");
var resultDiv = document.getElementById("mortgage-result");
var errorMsg = document.getElementById("error-message");
// Parse Values
var price = parseFloat(homePriceInput.value);
var down = parseFloat(downPaymentInput.value);
var annualRate = parseFloat(interestRateInput.value);
var years = parseInt(loanTermInput.value);
// Validation
if (isNaN(price) || isNaN(down) || isNaN(annualRate) || isNaN(years) || price <= 0) {
errorMsg.style.display = "block";
resultDiv.style.display = "none";
return;
} else {
errorMsg.style.display = "none";
}
// Calculation Logic
var principal = price – down;
// Handle edge case where down payment is greater than home price
if (principal < 0) {
alert("Down payment cannot be greater than home price.");
return;
}
// If 0% interest loan (unlikely but possible edge case)
var monthlyPayment = 0;
var totalInterest = 0;
var totalCost = 0;
if (annualRate === 0) {
monthlyPayment = principal / (years * 12);
totalCost = principal;
totalInterest = 0;
} else {
var monthlyRate = (annualRate / 100) / 12;
var numberOfPayments = years * 12;
// Amortization Formula
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var mathPower = Math.pow(1 + monthlyRate, numberOfPayments);
monthlyPayment = principal * ((monthlyRate * mathPower) / (mathPower – 1));
var totalPayments = monthlyPayment * numberOfPayments;
totalInterest = totalPayments – principal;
totalCost = totalPayments + down; // Total cost includes down payment + all payments
}
// Formatting Results
var formatter = new Intl.NumberFormat('en-US', {
style: 'currency',
currency: 'USD',
minimumFractionDigits: 2
});
// Update DOM
document.getElementById("display-loan-amount").innerHTML = formatter.format(principal);
document.getElementById("display-monthly-payment").innerHTML = formatter.format(monthlyPayment);
document.getElementById("display-total-interest").innerHTML = formatter.format(totalInterest);
document.getElementById("display-total-cost").innerHTML = formatter.format(totalCost);
// Show Results
resultDiv.style.display = "block";
}
Mortgage Payment Calculator
30 Years
20 Years
15 Years
10 Years
Please enter valid positive numbers for all fields.
Payment Summary
Loan Amount:
–
Monthly Payment: –
Total Interest Paid:
–
Total Cost of Loan:
–
*Taxes and insurance are not included in this calculation.
Understanding Your Mortgage Calculation
Purchasing a home is one of the most significant financial decisions you will make. This Mortgage Payment Calculator is designed to help you understand your potential monthly financial obligations before you sign on the dotted line. By inputting your home price, down payment, interest rate, and loan term, you can determine exactly how much principal and interest you will pay every month.
How the Mortgage Formula Works
While this calculator handles the heavy lifting, understanding the underlying math can be empowering. The standard formula used by lenders to calculate your fixed monthly mortgage payment (M) is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
- P (Principal): The loan amount (Home Price minus Down Payment).
- i (Monthly Interest Rate): Your annual interest rate divided by 12.
- n (Number of Payments): The loan term in years multiplied by 12.
Factors Affecting Your Monthly Payment
Several variables can significantly impact your monthly mortgage costs:
- Down Payment: A larger down payment reduces your principal loan amount, which lowers your monthly payment and the total interest paid over the life of the loan. Putting down at least 20% also helps you avoid Private Mortgage Insurance (PMI).
- Loan Term: A 30-year term offers lower monthly payments but results in higher total interest costs. Conversely, a 15-year term has higher monthly payments but saves you a substantial amount in interest.
- Interest Rate: Even a fraction of a percentage point difference in your rate can equal thousands of dollars in savings or costs over the life of a mortgage. Your credit score plays a major role in the rate lenders offer you.
Why Calculate Before You Buy?
Using a mortgage calculator allows you to budget effectively. Lenders look at your Debt-to-Income (DTI) ratio to determine eligibility. Knowing your estimated mortgage payment helps you ensure your housing costs do not exceed recommended limits (typically 28% of your gross monthly income).