Estimate your monthly auto loan payments based on vehicle price, down payment, and interest rates.
Monthly Payment:$0.00
Total Loan Amount:$0.00
Total Interest Paid:$0.00
Total Cost (Principal + Interest):$0.00
How to Calculate Your Car Loan Payment
Buying a car is one of the most significant financial decisions you'll make. Understanding your monthly obligation before visiting a dealership helps you stay within budget. Our car loan calculator uses the standard amortization formula to determine your fixed monthly payment.
Understanding the Variables
Vehicle Price: The total negotiated price of the car before taxes and fees.
Down Payment: The cash you pay upfront. A larger down payment reduces the loan principal and total interest paid.
Loan Term: The duration of the loan. While longer terms (72-84 months) lower monthly payments, they significantly increase the total interest you pay.
Interest Rate (APR): The annual cost of borrowing. This is heavily influenced by your credit score.
Example Calculation
If you purchase a vehicle for $30,000 with a $5,000 down payment at a 5% interest rate for 60 months:
Loan Principal: $25,000
Monthly Payment: $471.78
Total Interest Paid: $3,306.80
Tips for Lowering Your Payment
To secure the most affordable car loan, consider improving your credit score before applying, as this can shave percentage points off your interest rate. Additionally, aim for a "20/4/10" rule: put 20% down, limit the loan to 4 years (48 months), and ensure total transportation costs don't exceed 10% of your take-home pay.
function calculateCarLoan() {
var price = parseFloat(document.getElementById("vehiclePrice").value) || 0;
var down = parseFloat(document.getElementById("downPayment").value) || 0;
var trade = parseFloat(document.getElementById("tradeInValue").value) || 0;
var taxRate = parseFloat(document.getElementById("salesTax").value) || 0;
var term = parseFloat(document.getElementById("loanTerm").value) || 0;
var annualRate = parseFloat(document.getElementById("interestRate").value) || 0;
// Calculate Sales Tax on Price
var taxAmount = price * (taxRate / 100);
var totalPriceWithTax = price + taxAmount;
// Principal Loan Amount
var principal = totalPriceWithTax – down – trade;
if (principal <= 0) {
alert("Your down payment and trade-in cover the cost of the vehicle. No loan required.");
return;
}
if (term 0) {
var r = (annualRate / 100) / 12; // Monthly Interest Rate
var n = term; // Number of payments
// Amortization Formula: P [ r(1+r)^n ] / [ (1+r)^n – 1 ]
var pow = Math.pow(1 + r, n);
monthlyPayment = (principal * r * pow) / (pow – 1);
totalCost = monthlyPayment * n;
totalInterest = totalCost – principal;
} else {
// 0% Interest Case
monthlyPayment = principal / term;
totalInterest = 0;
totalCost = principal;
}
// Display results
document.getElementById("resMonthly").innerText = "$" + monthlyPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resLoanAmount").innerText = "$" + principal.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resTotalInterest").innerText = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resTotalCost").innerText = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("resultArea").style.display = "block";
}