Estimate your monthly car payments, total interest, and the true cost of your next vehicle.
Estimated Monthly Payment:—
Total Loan Amount:—
Total Interest Paid:—
Total Cost (Price + Tax + Interest):—
How to Use the Auto Loan Calculator
Buying a car is one of the most significant financial decisions you will make. Our Auto Loan Payment Calculator is designed to provide transparency into your monthly budget. By adjusting variables like the down payment, trade-in value, and loan term, you can see exactly how much car you can afford without overextending your finances.
The Formula Behind Your Car Payment
Car loan payments are calculated using an amortization formula. The math determines how much of your monthly payment goes toward the principal balance and how much goes toward the interest. The formula used is:
M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1 ]
Where:
M is your total monthly payment.
P is the principal loan amount (Vehicle price + Tax – Down payment).
i is your monthly interest rate (Annual rate divided by 12).
n is the total number of months in your loan term.
Key Factors That Affect Your Payment
Credit Score: This is the primary factor lenders use to determine your APR. Higher scores usually result in lower interest rates.
Loan Term: While a 72-month or 84-month loan results in lower monthly payments, you will pay significantly more in total interest over the life of the loan.
Down Payment: Putting at least 20% down helps avoid "gap" issues where you owe more than the car is worth (being underwater).
Sales Tax: Often overlooked, sales tax is usually calculated on the purchase price and can add thousands to the total loan amount.
Example Calculation
If you purchase a vehicle for $30,000 with a $5,000 down payment at a 5% APR for 60 months, and a 7% sales tax:
Tax Amount: $2,100
Total Loan Principal: $27,100 ($30,000 – $5,000 + $2,100)
Monthly Payment: Approximately $511.41
Total Interest Paid: $3,584.60
function calculateCarLoan() {
var price = parseFloat(document.getElementById('carPrice').value);
var down = parseFloat(document.getElementById('downPayment').value) || 0;
var trade = parseFloat(document.getElementById('tradeIn').value) || 0;
var rate = parseFloat(document.getElementById('interestRate').value);
var term = parseInt(document.getElementById('loanTerm').value);
var taxRate = parseFloat(document.getElementById('salesTax').value) || 0;
if (isNaN(price) || isNaN(rate) || isNaN(term) || price <= 0 || term <= 0) {
alert("Please enter valid positive numbers for price, interest rate, and term.");
return;
}
// Calculation Logic
var taxAmount = price * (taxRate / 100);
var principal = price – down – trade + taxAmount;
if (principal <= 0) {
document.getElementById('resMonthly').innerHTML = "$0.00";
document.getElementById('resPrincipal').innerHTML = "$0.00";
document.getElementById('resInterest').innerHTML = "$0.00";
document.getElementById('resTotalCost').innerHTML = "$" + (price + taxAmount).toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resultsBox').style.display = 'block';
return;
}
var monthlyRate = (rate / 100) / 12;
var emi = 0;
if (rate === 0) {
emi = principal / term;
} else {
emi = principal * (monthlyRate * Math.pow(1 + monthlyRate, term)) / (Math.pow(1 + monthlyRate, term) – 1);
}
var totalPayment = emi * term;
var totalInterest = totalPayment – principal;
var totalCost = totalPayment + down + trade;
// Display Results
document.getElementById('resMonthly').innerHTML = "$" + emi.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resPrincipal').innerHTML = "$" + principal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resInterest').innerHTML = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resTotalCost').innerHTML = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('resultsBox').style.display = 'block';
// Smooth scroll to results
document.getElementById('resultsBox').scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}