Estimate your monthly auto payments and total interest.
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Monthly Payment:–
Total Loan Amount:–
Total Interest Paid:–
Total Cost (w/ Tax & Fees):–
Estimated Payoff Date:–
Understanding Your Car Loan Options
Purchasing a vehicle is one of the largest financial commitments most people make, second only to buying a home. Our Car Loan Calculator helps you navigate the complexities of auto financing by breaking down your monthly payments, interest costs, and total loan obligations.
How This Calculator Works
To get the most accurate estimate, it's important to understand the input fields:
Vehicle Price: The sticker price of the car you intend to buy.
Down Payment & Trade-in: Cash upfront or the value of your old car reduces the principal loan amount, saving you money on interest.
APR (Annual Percentage Rate): This is the cost of borrowing money. A lower credit score typically results in a higher APR.
Loan Term: Common terms are 36, 48, 60, or 72 months. Longer terms lower your monthly payment but increase the total interest paid over the life of the loan.
Taxes & Fees: Sales tax and dealer documentation fees are often rolled into the loan, increasing your monthly payment.
Calculation Example
Let's say you are buying a car for $35,000. You have a trade-in worth $5,000 and put down another $2,000 in cash.
If the sales tax is 7% ($2,450) and fees are $500, your total cost basis is $37,950. After subtracting your down payment and trade-in ($7,000), your loan amount is $30,950.
With a 5% interest rate over a 60-month term, your monthly payment would be approximately $584. Over those 5 years, you would pay roughly $4,095 in interest alone.
Tips for Lowering Your Auto Loan
Shorten the Term: While a 72-month loan looks attractive due to lower monthly payments, you will pay significantly more in interest than with a 48 or 60-month loan.
Put 20% Down: Aiming for a 20% down payment helps you avoid "being underwater" on the loan (owing more than the car is worth) as soon as you drive off the lot.
Shop for Rates: Don't just accept the dealer's financing. Check with local credit unions or your bank to see if they offer competitive auto loan rates.
function calculateAutoLoan() {
// 1. Get Values
var price = parseFloat(document.getElementById("vehiclePrice").value) || 0;
var downPayment = parseFloat(document.getElementById("downPayment").value) || 0;
var tradeIn = parseFloat(document.getElementById("tradeInValue").value) || 0;
var interestRate = parseFloat(document.getElementById("interestRate").value) || 0;
var months = parseFloat(document.getElementById("loanTerm").value) || 0;
var taxRate = parseFloat(document.getElementById("salesTax").value) || 0;
var fees = parseFloat(document.getElementById("dealerFees").value) || 0;
// 2. Validate essential inputs
if (price <= 0 || months <= 0) {
alert("Please enter a valid Vehicle Price and Loan Term.");
return;
}
// 3. Logic
// Calculate Tax Amount
var taxAmount = price * (taxRate / 100);
// Net Cost of Vehicle before credits (Price + Tax + Fees)
var totalCostBasis = price + taxAmount + fees;
// Loan Amount (Principal) = Cost Basis – Down Payment – Trade In
var loanAmount = totalCostBasis – downPayment – tradeIn;
if (loanAmount < 0) {
loanAmount = 0;
}
var monthlyPayment = 0;
var totalInterest = 0;
var totalCost = 0;
if (interestRate === 0) {
// Simple division if 0% APR
monthlyPayment = loanAmount / months;
totalInterest = 0;
} else {
// Amortization Formula: P * (r(1+r)^n) / ((1+r)^n – 1)
var monthlyRate = (interestRate / 100) / 12;
var mathPow = Math.pow(1 + monthlyRate, months);
monthlyPayment = loanAmount * ((monthlyRate * mathPow) / (mathPow – 1));
// Total cost of loan payments
var totalPayments = monthlyPayment * months;
totalInterest = totalPayments – loanAmount;
}
// Total Cost of the Car Purchase (Down + Trade + Total Payments made)
totalCost = downPayment + tradeIn + (monthlyPayment * months);
// 4. Calculate Payoff Date
var today = new Date();
var futureDate = new Date(today.setMonth(today.getMonth() + months));
var monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
var dateString = monthNames[futureDate.getMonth()] + " " + futureDate.getFullYear();
// 5. Output Results
document.getElementById("monthlyPaymentDisplay").innerText = "$" + monthlyPayment.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalLoanDisplay").innerText = "$" + loanAmount.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalInterestDisplay").innerText = "$" + totalInterest.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("totalCostDisplay").innerText = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById("payoffDateDisplay").innerText = dateString;
// Show results
document.getElementById("results").style.display = "block";
}