Purchasing a vehicle is a major financial decision. Our car loan calculator helps you break down the true cost of ownership by including taxes, trade-ins, and interest. Here is how to use each field effectively:
Vehicle Price: The sticker price of the car or the negotiated price before any fees.
Down Payment: The cash you are paying upfront. A higher down payment reduces your monthly cost and interest paid.
Trade-in Value: The amount a dealer gives you for your current vehicle. In many states, this can also reduce the sales tax you owe.
Interest Rate: The Annual Percentage Rate (APR) provided by your lender.
Loan Term: Common terms are 60 or 72 months. While longer terms lower your monthly payment, you will pay more in total interest.
Real-World Example Calculation
Imagine you are buying a car for $30,000 with a $5,000 down payment and a $3,000 trade-in. If your interest rate is 5% for 60 months and your state tax is 7%:
Tax is calculated on the price: $30,000 * 0.07 = $2,100.
Using the amortization formula, your monthly payment would be approximately $454.80.
The total interest paid over 5 years would be roughly $3,188.
Tips for a Better Car Loan
To secure the best deal, check your credit score before applying. A score above 700 usually qualifies for the lowest interest rates. Additionally, consider getting pre-approved by a credit union or bank before visiting the dealership to use as leverage during negotiations.
function calculateCarLoan() {
var price = parseFloat(document.getElementById('car_price').value);
var downPayment = parseFloat(document.getElementById('down_payment').value) || 0;
var tradeIn = parseFloat(document.getElementById('trade_in').value) || 0;
var rate = parseFloat(document.getElementById('interest_rate').value);
var term = parseInt(document.getElementById('loan_term').value);
var taxRate = parseFloat(document.getElementById('sales_tax').value) || 0;
if (isNaN(price) || isNaN(rate) || isNaN(term) || price <= 0) {
alert("Please enter valid numbers for price, interest rate, and term.");
return;
}
// Calculation Logic
var taxAmount = price * (taxRate / 100);
var principal = price + taxAmount – downPayment – tradeIn;
if (principal <= 0) {
document.getElementById('monthly_payment').innerHTML = "$0.00";
document.getElementById('total_loan').innerHTML = "$0.00";
document.getElementById('total_interest').innerHTML = "$0.00";
document.getElementById('total_tax').innerHTML = "$" + taxAmount.toFixed(2);
document.getElementById('total_cost').innerHTML = "$" + (price + taxAmount).toFixed(2);
document.getElementById('results_box').style.display = "block";
return;
}
var monthlyRate = (rate / 100) / 12;
var monthlyPayment = 0;
if (rate === 0) {
monthlyPayment = principal / term;
} else {
monthlyPayment = principal * (monthlyRate * Math.pow(1 + monthlyRate, term)) / (Math.pow(1 + monthlyRate, term) – 1);
}
var totalCostOfLoan = monthlyPayment * term;
var totalInterest = totalCostOfLoan – principal;
var totalCostOfCar = totalCostOfLoan + downPayment + tradeIn;
// Display Results
document.getElementById('monthly_payment').innerHTML = "$" + monthlyPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('total_loan').innerHTML = "$" + principal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('total_interest').innerHTML = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('total_tax').innerHTML = "$" + taxAmount.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('total_cost').innerHTML = "$" + totalCostOfCar.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('results_box').style.display = "block";
}