Monthly Payment: $0.00
Total Loan Amount: $0.00 | Total Interest Paid: $0.00
Understanding Your Car Loan
This Car Loan Calculator helps you estimate your monthly payments, the total amount financed, and the total interest you'll pay over the life of your car loan. It also accounts for sales tax and additional fees, providing a more realistic picture of your total car ownership costs.
How the Calculation Works
The calculator uses standard financial formulas to determine your loan payments. Here's a breakdown:
Total Price Before Tax: This is the initial price of the car.
Sales Tax Amount: Calculated by applying the Sales Tax Rate to the Car Price.
Total Price With Tax: The sum of the Car Price and the Sales Tax Amount.
Total Loan Amount: This is the Total Price With Tax minus the Down Payment, plus any Additional Fees. This is the principal amount you are borrowing.
Monthly Interest Rate: The Annual Interest Rate is divided by 12.
Number of Payments: The Loan Term (in years) is multiplied by 12.
Monthly Payment: Calculated using the loan amortization formula:
$M = P [ i(1 + i)^n ] / [ (1 + i)^n – 1]$
Where:
M = Monthly Payment
P = Principal Loan Amount (Total Loan Amount)
i = Monthly Interest Rate
n = Total Number of Payments
Total Paid: The Monthly Payment multiplied by the Number of Payments.
Total Interest Paid: The Total Paid minus the Total Loan Amount.
Key Inputs Explained
Car Price: The sticker price or agreed-upon price of the vehicle before taxes and fees.
Down Payment: The upfront amount you pay towards the car's purchase. A larger down payment reduces the amount you need to borrow.
Loan Term: The duration of the loan, usually expressed in years. Longer terms mean lower monthly payments but more interest paid overall.
Annual Interest Rate: The yearly rate charged by the lender, expressed as a percentage. This significantly impacts your total cost.
Sales Tax Rate: The percentage of sales tax applied to the car's price based on your location.
Additional Fees: Any other one-time fees associated with the loan or vehicle purchase, such as documentation fees, registration fees, etc.
Why Use This Calculator?
Before signing on the dotted line, understanding your potential car loan is crucial. This calculator helps you:
Compare different loan offers.
Determine affordability based on your budget.
See the impact of varying interest rates, loan terms, and down payments.
Factor in taxes and fees for a comprehensive estimate.
Remember, this is an estimate. Actual loan terms, rates, and fees may vary. Consult with your lender for precise figures.
function calculateCarLoan() {
var carPrice = parseFloat(document.getElementById("carPrice").value);
var downPayment = parseFloat(document.getElementById("downPayment").value);
var loanTermYears = parseInt(document.getElementById("loanTerm").value);
var annualInterestRate = parseFloat(document.getElementById("interestRate").value);
var salesTaxRate = parseFloat(document.getElementById("salesTax").value);
var additionalFees = parseFloat(document.getElementById("additionalFees").value);
var resultDiv = document.getElementById("result");
if (isNaN(carPrice) || isNaN(downPayment) || isNaN(loanTermYears) || isNaN(annualInterestRate) || isNaN(salesTaxRate) || isNaN(additionalFees)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (carPrice <= 0 || loanTermYears <= 0 || annualInterestRate < 0 || salesTaxRate < 0 || additionalFees < 0) {
resultDiv.innerHTML = "Please enter positive values for price, term, and non-negative values for rates/fees.";
return;
}
var salesTaxAmount = carPrice * (salesTaxRate / 100);
var totalPriceWithTax = carPrice + salesTaxAmount;
var totalLoanAmount = totalPriceWithTax – downPayment + additionalFees;
if (totalLoanAmount 0) {
monthlyPayment = totalLoanAmount / numberOfPayments;
} else {
monthlyPayment = totalLoanAmount; // If term is 0, pay it all now
}
} else {
// Standard amortization formula
monthlyPayment = totalLoanAmount * (monthlyInterestRate * Math.pow(1 + monthlyInterestRate, numberOfPayments)) / (Math.pow(1 + monthlyInterestRate, numberOfPayments) – 1);
}
// Ensure monthly payment is not NaN and is formatted correctly
if (isNaN(monthlyPayment) || monthlyPayment === Infinity) {
monthlyPayment = 0;
}
totalPaid = monthlyPayment * numberOfPayments;
totalInterestPaid = totalPaid – totalLoanAmount;
// Ensure results are not negative due to floating point inaccuracies or edge cases
if (totalInterestPaid < 0) totalInterestPaid = 0;
if (totalPaid < 0) totalPaid = 0;
if (monthlyPayment < 0) monthlyPayment = 0;
resultDiv.innerHTML =
"Monthly Payment: $" + monthlyPayment.toFixed(2) +
" | Total Loan Amount: $" + totalLoanAmount.toFixed(2) + " | Total Interest Paid: $" + totalInterestPaid.toFixed(2) + "";
}