function calculateComparison() {
// Get Buying Values
var buyPrice = parseFloat(document.getElementById('purchasePrice').value) || 0;
var buyDown = parseFloat(document.getElementById('buyDownPayment').value) || 0;
var buyTerm = parseFloat(document.getElementById('buyTerm').value) || 1;
var buyRate = parseFloat(document.getElementById('buyInterestRate').value) / 100 / 12;
var resale = parseFloat(document.getElementById('resaleValue').value) || 0;
// Get Leasing Values
var leaseMonthly = parseFloat(document.getElementById('leaseMonthly').value) || 0;
var leaseDown = parseFloat(document.getElementById('leaseDownPayment').value) || 0;
var leaseTerm = parseFloat(document.getElementById('leaseTerm').value) || 1;
var leaseSec = parseFloat(document.getElementById('leaseSecurity').value) || 0;
// Buying Calculation
var loanAmount = buyPrice – buyDown;
var buyMonthlyPayment = 0;
if (buyRate > 0) {
buyMonthlyPayment = loanAmount * (buyRate * Math.pow(1 + buyRate, buyTerm)) / (Math.pow(1 + buyRate, buyTerm) – 1);
} else {
buyMonthlyPayment = loanAmount / buyTerm;
}
// Total cost over the lease term equivalent period for fair comparison
// We normalize to the lease term to see cost per month of usage
var totalBuyPaid = (buyMonthlyPayment * leaseTerm) + buyDown;
// Estimated depreciation over that specific period
var depreciationPerMonth = (buyPrice – resale) / buyTerm;
var netBuyCost = (depreciationPerMonth * leaseTerm) + (buyMonthlyPayment * leaseTerm – (loanAmount / buyTerm * leaseTerm));
// Simplified: Total Buying Cost = (Payments + Down) – Resale Value
var actualBuyCost = (buyMonthlyPayment * buyTerm) + buyDown – resale;
// Leasing Calculation
var actualLeaseCost = (leaseMonthly * leaseTerm) + leaseDown;
// UI Updates
document.getElementById('results').style.display = 'block';
document.getElementById('buyTotalCost').innerText = '$' + actualBuyCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('buyMonthlyDetail').innerText = 'Monthly Loan: $' + buyMonthlyPayment.toFixed(2);
document.getElementById('leaseTotalCost').innerText = '$' + actualLeaseCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('leaseMonthlyDetail').innerText = 'Total for ' + leaseTerm + ' months';
var verdict = document.getElementById('verdict');
var buyBox = document.getElementById('buyResultBox');
var leaseBox = document.getElementById('leaseResultBox');
if (actualBuyCost < actualLeaseCost) {
var diff = actualLeaseCost – actualBuyCost;
verdict.innerText = 'Buying is more cost-effective by $' + diff.toLocaleString() + ' over the term.';
buyBox.style.background = '#c6f6d5';
leaseBox.style.background = '#fff5f5';
} else {
var diff = actualBuyCost – actualLeaseCost;
verdict.innerText = 'Leasing is more cost-effective by $' + diff.toLocaleString() + ' over the term.';
leaseBox.style.background = '#c6f6d5';
buyBox.style.background = '#fff5f5';
}
}
Understanding Lease vs. Buy: Which is Better for Your Wallet?
Deciding whether to lease or buy a new car is one of the most common financial dilemmas for drivers. While buying is often seen as the more "traditional" path, leasing offers lower monthly payments and the ability to drive a newer vehicle every few years. This calculator helps you compare the total cost of ownership for both options.
Key Differences Explained
Buying: When you buy, you own the vehicle. You pay for the entire value of the car plus interest. However, once the loan is paid off, you have an asset (equity) that you can sell or trade in.
Leasing: When you lease, you are essentially "renting" the car for its most depreciable years. You only pay for the difference between the purchase price and the residual value (what the car is worth at the end of the lease), plus fees and interest (known as the "money factor").
The Role of Depreciation
Depreciation is the single biggest cost of vehicle ownership. A new car typically loses 20% of its value in the first year and roughly 60% after five years. When you use the Lease vs. Buy Car Calculator, the "Estimated Resale Value" is the most critical factor for the buying side. If the car holds its value well (like a Jeep Wrangler or a Toyota Tacoma), buying usually wins. If the car depreciates rapidly (like many luxury sedans), leasing might be the smarter financial move.
Pros and Cons at a Glance
Buying Pros
Total ownership of the asset
No mileage restrictions
No "wear and tear" charges
Cheaper in the long run (5+ years)
Leasing Pros
Lower monthly payments
Minimal down payment required
Always under factory warranty
Latest technology and safety features
Financial Considerations
When using this tool, remember to look beyond the monthly payment. A $400 lease payment might look better than a $600 loan payment, but at the end of the lease, you have $0 equity. At the end of a loan, you might have a car worth $15,000. Our calculator accounts for this by subtracting the Estimated Resale Value from the total cost of buying to give you a true "net cost" comparison.
SEO Tip: If you are planning to keep a car for more than 4 years, buying is almost always the financially superior choice. If you enjoy upgrading your vehicle frequently and drive less than 12,000 miles per year, leasing provides convenience and predictable costs.