Auto Loan Calculator
/* Calculator Styles */
.calc-wrapper {
max-width: 800px;
margin: 20px auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
background: #fff;
border: 1px solid #e2e8f0;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
padding: 0;
overflow: hidden;
}
.calc-header {
background: #2c3e50;
color: white;
padding: 20px;
text-align: center;
}
.calc-header h2 {
margin: 0;
font-size: 24px;
}
.calc-body {
padding: 30px;
display: flex;
flex-wrap: wrap;
gap: 30px;
}
.calc-inputs {
flex: 1;
min-width: 300px;
}
.calc-results {
flex: 1;
min-width: 300px;
background: #f8f9fa;
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;
color: #4a5568;
font-size: 14px;
}
.input-wrapper {
position: relative;
}
.input-wrapper input {
width: 100%;
padding: 10px 10px 10px 35px; /* space for symbol */
border: 1px solid #cbd5e0;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.input-wrapper.no-symbol input {
padding-left: 10px;
}
.input-symbol {
position: absolute;
left: 12px;
top: 50%;
transform: translateY(-50%);
color: #718096;
}
.btn-calc {
width: 100%;
background: #3182ce;
color: white;
border: none;
padding: 12px;
font-size: 16px;
font-weight: bold;
border-radius: 6px;
cursor: pointer;
margin-top: 10px;
transition: background 0.2s;
}
.btn-calc:hover {
background: #2b6cb0;
}
.result-row {
display: flex;
justify-content: space-between;
align-items: center;
margin-bottom: 15px;
padding-bottom: 15px;
border-bottom: 1px solid #e2e8f0;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
font-size: 14px;
color: #4a5568;
}
.result-value {
font-size: 18px;
font-weight: bold;
color: #2d3748;
}
.main-result {
text-align: center;
margin-bottom: 25px;
background: #ebf8ff;
padding: 20px;
border-radius: 8px;
border: 1px solid #bee3f8;
}
.main-result .label {
font-size: 14px;
color: #2b6cb0;
text-transform: uppercase;
letter-spacing: 1px;
font-weight: bold;
margin-bottom: 5px;
}
.main-result .value {
font-size: 36px;
color: #2c5282;
font-weight: 800;
}
/* Article Styles */
.article-container {
max-width: 800px;
margin: 40px auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
line-height: 1.6;
color: #2d3748;
}
.article-container h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #3182ce;
padding-bottom: 10px;
display: inline-block;
}
.article-container p {
margin-bottom: 15px;
font-size: 16px;
}
.article-container ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-container li {
margin-bottom: 8px;
}
.faq-block {
background: #f7fafc;
padding: 20px;
border-radius: 8px;
margin-top: 20px;
}
.faq-question {
font-weight: bold;
font-size: 18px;
color: #2d3748;
margin-bottom: 10px;
}
Total Loan Amount:
$0.00
Total Interest Paid:
$0.00
Sales Tax Amount:
$0.00
Total Cost of Car:
$0.00
How to Use This Auto Loan Calculator
Purchasing a vehicle is a significant financial commitment. This Auto Loan Calculator is designed to help you understand exactly how much you will pay per month and over the life of your loan. By inputting factors like the vehicle price, your down payment, trade-in value, and local sales tax, you can get a realistic estimate of your financing costs.
Unlike generic loan calculators, this tool accounts for Sales Tax and Trade-in Value, two critical components that drastically affect the final loan amount. Often, buyers forget to calculate tax, leading to a higher monthly payment than expected at the dealership.
Understanding Your Loan Factors
- Vehicle Price: The negotiated price of the car before taxes and fees.
- Down Payment: Cash you pay upfront to reduce the loan amount. A higher down payment lowers your monthly bill and interest costs.
- Trade-in Value: The amount the dealer gives you for your old car, which is deducted from the new car's price.
- APR (Interest Rate): The annual percentage rate charged by the lender. Your credit score heavily influences this number.
- Loan Term: How long you have to pay off the loan. Common terms are 36, 48, 60, or 72 months. Longer terms lower monthly payments but increase total interest paid.
How Sales Tax Affects Your Auto Loan
In most states, sales tax is applied to the vehicle price before rebates but often after trade-in deductions (depending on state laws). This calculator estimates tax based on the vehicle price to give you a conservative estimate of the total amount financed. Remember, fees for title and registration are separate and vary by location.
What is a good APR for a car loan?
Interest rates fluctuate based on the economy and your credit score. Generally, a "good" rate for a new car is below 5-6% for borrowers with excellent credit, while used car rates are typically 1-2% higher.
Should I choose a longer loan term?
While a 72 or 84-month loan reduces your monthly payment, it significantly increases the total interest you pay. Additionally, you risk becoming "upside-down" on the loan (owing more than the car is worth) for a longer period.
function calculateAutoLoan() {
// 1. Get Input Values
var price = parseFloat(document.getElementById("vehiclePrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var tradeIn = parseFloat(document.getElementById("tradeInValue").value);
var taxRate = parseFloat(document.getElementById("salesTax").value);
var interestRate = parseFloat(document.getElementById("interestRate").value);
var termMonths = parseFloat(document.getElementById("loanTerm").value);
// 2. Validation
if (isNaN(price) || price < 0) price = 0;
if (isNaN(downPayment) || downPayment < 0) downPayment = 0;
if (isNaN(tradeIn) || tradeIn < 0) tradeIn = 0;
if (isNaN(taxRate) || taxRate < 0) taxRate = 0;
if (isNaN(interestRate) || interestRate < 0) interestRate = 0;
if (isNaN(termMonths) || termMonths <= 0) termMonths = 1;
// 3. Logic specific to Auto Loans
// Calculate Tax Amount (Usually tax is on Price, sometimes Price – TradeIn depending on state,
// here we assume Tax on Price for a conservative estimate or (Price – TradeIn) is common too.
// We will calculate Tax on (Price – TradeIn) as it is a common benefit in many states).
var taxableAmount = Math.max(0, price – tradeIn);
var taxAmount = taxableAmount * (taxRate / 100);
// Total Amount to Finance = (Price + Tax) – Down Payment – Trade In
// Note: If Trade In was already deducted for tax, we don't deduct it again from the basis,
// we just deduct it from the total cash flow.
// Formula: Net Price = Price + Tax – Down – TradeIn
var loanAmount = (price + taxAmount) – downPayment – tradeIn;
if (loanAmount < 0) {
loanAmount = 0;
}
var monthlyInterestRate = (interestRate / 100) / 12;
var monthlyPayment = 0;
var totalInterest = 0;
// 4. Amortization Calculation
if (interestRate === 0) {
monthlyPayment = loanAmount / termMonths;
totalInterest = 0;
} else {
// M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
var x = Math.pow(1 + monthlyInterestRate, termMonths);
monthlyPayment = loanAmount * ((monthlyInterestRate * x) / (x – 1));
totalInterest = (monthlyPayment * termMonths) – loanAmount;
}
var totalCost = price + taxAmount + totalInterest; // Total cost of owning the car (excluding down payment? No, typically Price + Interest + Tax)
// 5. Update DOM
document.getElementById("monthlyPayment").innerHTML = "$" + formatMoney(monthlyPayment);
document.getElementById("totalLoanAmount").innerHTML = "$" + formatMoney(loanAmount);
document.getElementById("totalInterest").innerHTML = "$" + formatMoney(totalInterest);
document.getElementById("totalTax").innerHTML = "$" + formatMoney(taxAmount);
document.getElementById("totalCost").innerHTML = "$" + formatMoney(totalCost);
}
function formatMoney(number) {
return number.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}
// Initialize on load
window.onload = function() {
calculateAutoLoan();
};