.auto-loan-calculator-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;
}
.alc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 768px) {
.alc-grid { grid-template-columns: 1fr; }
}
.alc-input-group {
margin-bottom: 15px;
}
.alc-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #333;
font-size: 0.95rem;
}
.alc-input-group input, .alc-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
box-sizing: border-box;
}
.alc-input-group input:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 0 2px rgba(0,123,255,0.25);
}
.alc-btn {
background-color: #007bff;
color: white;
border: none;
padding: 12px 20px;
font-size: 1rem;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background-color 0.2s;
}
.alc-btn:hover {
background-color: #0056b3;
}
.alc-results {
background-color: #f8f9fa;
padding: 20px;
border-radius: 6px;
margin-top: 25px;
border-left: 5px solid #007bff;
display: none;
}
.alc-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #e9ecef;
}
.alc-result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.alc-result-label {
color: #555;
}
.alc-result-value {
font-weight: bold;
color: #212529;
}
.alc-highlight {
font-size: 1.5rem;
color: #28a745;
}
.seo-article {
margin-top: 40px;
line-height: 1.6;
color: #333;
}
.seo-article h2 {
margin-top: 30px;
color: #2c3e50;
}
.seo-article h3 {
color: #34495e;
}
.seo-article ul {
margin-bottom: 20px;
}
.error-msg {
color: #dc3545;
display: none;
margin-top: 10px;
font-size: 0.9rem;
}
function calculateAutoLoan() {
// Get Input Values
var price = parseFloat(document.getElementById('vehiclePrice').value);
var taxRate = parseFloat(document.getElementById('salesTax').value) || 0;
var downPayment = parseFloat(document.getElementById('downPayment').value) || 0;
var tradeValue = parseFloat(document.getElementById('tradeInValue').value) || 0;
var tradeOwed = parseFloat(document.getElementById('tradeInOwed').value) || 0;
var interestRate = parseFloat(document.getElementById('interestRate').value);
var months = parseInt(document.getElementById('loanTerm').value);
// Validation
if (isNaN(price) || isNaN(interestRate) || price <= 0) {
document.getElementById('errorMsg').style.display = 'block';
document.getElementById('loanResult').style.display = 'none';
return;
}
document.getElementById('errorMsg').style.display = 'none';
// Calculations
// 1. Calculate Tax (Assuming tax is on full vehicle price – common in many states)
var taxAmount = price * (taxRate / 100);
// 2. Net Trade-In Equity (Can be negative)
var tradeEquity = tradeValue – tradeOwed;
// 3. Amount to Finance (Price + Tax – Down Payment – Trade Equity)
// Note: If Trade Equity is negative, it ADDS to the loan (rolling over negative equity)
var amountFinanced = (price + taxAmount) – downPayment – tradeEquity;
// Handle edge case where down payment covers everything
if (amountFinanced 0) {
if (interestRate === 0) {
monthlyPayment = amountFinanced / months;
} else {
var monthlyRate = (interestRate / 100) / 12;
// Formula: M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
monthlyPayment = amountFinanced * (monthlyRate * Math.pow(1 + monthlyRate, months)) / (Math.pow(1 + monthlyRate, months) – 1);
}
var totalPayments = monthlyPayment * months;
totalInterest = totalPayments – amountFinanced;
}
// 5. Total Cost of Car
// Total payments made + Down Payment + Net Trade Equity (value used toward car)
var totalCost = (monthlyPayment * months) + downPayment + (tradeEquity > 0 ? tradeEquity : 0);
// Display Results
document.getElementById('displayMonthly').innerHTML = '$' + monthlyPayment.toFixed(2);
document.getElementById('displayLoanAmount').innerHTML = '$' + amountFinanced.toFixed(2);
document.getElementById('displayTax').innerHTML = '$' + taxAmount.toFixed(2);
document.getElementById('displayInterest').innerHTML = '$' + totalInterest.toFixed(2);
document.getElementById('displayTotalCost').innerHTML = '$' + totalCost.toFixed(2);
// Show Result Box
document.getElementById('loanResult').style.display = 'block';
}
Auto Loan Calculator with Trade-In
36 Months (3 Years)
48 Months (4 Years)
60 Months (5 Years)
72 Months (6 Years)
84 Months (7 Years)
Please enter valid positive numbers for price and interest rate.
Estimated Monthly Payment:
$0.00
Total Loan Amount (Financed):
$0.00
Total Sales Tax:
$0.00
Total Interest Cost:
$0.00
Total Cost of Car (Loan + Down + Trade Equity):
$0.00
Understanding Auto Loan Calculations
Purchasing a vehicle involves more than just the sticker price. When financing a car, truck, or SUV, several factors influence your final monthly payment. This Auto Loan Calculator is designed to provide a comprehensive view of your finances by incorporating trade-ins, negative equity, and sales tax.
How Trade-In Equity Affects Your Loan
Your trade-in can significantly alter your financing terms. There are two scenarios to consider:
- Positive Equity: If your car is worth $15,000 and you owe $10,000, you have $5,000 in positive equity. This acts like a down payment, reducing the amount you need to borrow.
- Negative Equity (Upside Down): If your car is worth $15,000 but you owe $20,000, you have -$5,000 in equity. Lenders often allow you to roll this amount into your new loan, but it increases your monthly payment and interest costs.
The Impact of Sales Tax and Fees
Many buyers forget to factor in sales tax, which can add thousands to the total cost. In most states, sales tax is calculated on the full purchase price of the new vehicle before trade-ins or rebates are applied. Our calculator adds this tax to your loan amount automatically to prevent payment shock at the dealership.
Interest Rates (APR) and Loan Terms
The Annual Percentage Rate (APR) is the cost of borrowing money. A lower APR saves you money over the life of the loan. Additionally, while extending your loan term from 60 to 84 months lowers your monthly payment, it drastically increases the total interest paid. Use the calculator above to compare how a 36-month term versus a 72-month term changes your total cost.