function calculateComparison() {
// Inputs for Buying
var buyPrice = parseFloat(document.getElementById('buyPrice').value) || 0;
var buyDown = parseFloat(document.getElementById('buyDownPayment').value) || 0;
var buyRate = (parseFloat(document.getElementById('buyInterest').value) || 0) / 100 / 12;
var buyMonths = parseInt(document.getElementById('buyTerm').value) || 0;
var buyResale = parseFloat(document.getElementById('buyResale').value) || 0;
// Inputs for Leasing
var leaseMonthly = parseFloat(document.getElementById('leaseMonthly').value) || 0;
var leaseUpfront = parseFloat(document.getElementById('leaseUpfront').value) || 0;
var leaseMonths = parseInt(document.getElementById('leaseTerm').value) || 0;
var leaseFees = parseFloat(document.getElementById('leaseFees').value) || 0;
// Loan Calculation
var loanPrincipal = buyPrice – buyDown;
var monthlyLoanPayment = 0;
if (buyRate > 0) {
monthlyLoanPayment = (loanPrincipal * buyRate * Math.pow(1 + buyRate, buyMonths)) / (Math.pow(1 + buyRate, buyMonths) – 1);
} else {
monthlyLoanPayment = loanPrincipal / buyMonths;
}
var totalLoanPayments = monthlyLoanPayment * buyMonths;
var grossBuyCost = totalLoanPayments + buyDown;
var netBuyCost = grossBuyCost – buyResale;
// Lease Calculation
var totalLeaseCost = (leaseMonthly * leaseMonths) + leaseUpfront + leaseFees;
// Display Logic
document.getElementById('results-area').style.display = 'block';
document.getElementById('totalBuyCost').innerText = '$' + netBuyCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('buyMonthlyDetail').innerText = 'Monthly Payment: $' + monthlyLoanPayment.toLocaleString(undefined, {maximumFractionDigits: 2});
document.getElementById('totalLeaseCost').innerText = '$' + totalLeaseCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('leaseMonthlyDetail').innerText = 'Term: ' + leaseMonths + ' months';
var verdict = document.getElementById('verdict');
// Comparing on a per-month basis since terms might differ
var buyMonthlyCost = netBuyCost / buyMonths;
var leaseMonthlyCost = totalLeaseCost / leaseMonths;
if (buyMonthlyCost < leaseMonthlyCost) {
verdict.innerText = "Buying is financially better in the long run! You save roughly $" + (leaseMonthlyCost – buyMonthlyCost).toFixed(2) + " per month.";
verdict.style.backgroundColor = "#e8f5e9";
verdict.style.color = "#2e7d32";
} else {
verdict.innerText = "Leasing is cheaper for this specific term! You save roughly $" + (buyMonthlyCost – leaseMonthlyCost).toFixed(2) + " per month.";
verdict.style.backgroundColor = "#fff3e0";
verdict.style.color = "#e65100";
}
}
Understanding Car Lease vs. Buy: A Comprehensive Financial Guide
Choosing between leasing and buying a car is one of the most debated financial decisions for consumers. Both options offer distinct advantages depending on your driving habits, budget, and long-term financial goals. Our Car Lease vs. Buy Calculator is designed to help you strip away the sales jargon and look purely at the math.
The True Cost of Ownership
When you buy a car, your "Net Cost" is the total amount paid (down payment + all loan payments) minus the cash value of the car when you decide to sell it. When you lease, you are essentially paying for the depreciation of the vehicle during the 2-4 years you drive it, plus interest (known as the money factor) and fees.
Calculation Example: The $35,000 Sedan
Imagine you are looking at a vehicle with a MSRP of $35,000. Here is how the math usually breaks down over a 5-year period for buying versus a 3-year lease:
Buying Case: You put $5,000 down and finance $30,000 at 5.5% for 60 months. Your payment is $573. After 5 years, you own the car, which might be worth $15,000. Your total net cost is roughly $24,380.
Lease Case: You pay $2,500 at signing and $450/month for 36 months. At the end of 3 years, you return the car. Your total cost is $18,700. However, you have no asset to sell at the end.
Key Factors to Consider
Feature
Buying
Leasing
Ownership
You own the asset eventually.
You return the car after the term.
Monthly Payments
Higher monthly payments.
Lower monthly payments.
Mileage Limits
Unlimited driving.
Usually 10k-15k miles per year.
Customization
Full freedom to modify.
Must keep car in original condition.
Who Should Lease?
Leasing is ideal for individuals who enjoy driving a new car every few years, want to avoid major repair costs (as the car is usually under warranty), and drive a predictable number of miles. It is also often a preferred choice for business owners who can utilize lease payments as a tax deduction.
Who Should Buy?
Buying is the superior financial choice for those who plan to keep their vehicle for 6-10 years. Once the loan is paid off, you have years of "payment-free" driving, which significantly reduces your long-term cost of transportation. It's also the only choice for high-mileage drivers who would face steep penalties on a lease contract.