Most lease-vs-buy tools stop at "here's your monthly payment." This one estimates your resale equity, flags mileage overage fees before they surprise you, and tells you whether you'll need tires or brakes before you're done — so you can compare what each option actually costs you, not just what it costs per month.
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How this calculator works
A lease payment is almost always smaller than a loan payment on the same car, and that's not a trick — you're only paying for the part of the car you use up, plus interest. The trick is what happens after 36 months: the lessee hands back the keys and starts over, while the buyer has a car worth real money. This calculator puts both on the same timeline and compares the net cost — everything you paid, minus what you'd have left.
A standard auto loan at the current average rate (pulled weekly from FRED, or your own APR), sales tax and fees up front, and a depreciation curve built from two numbers you can adjust: the immediate "drive-off" drop for a new vehicle (9% by default) and how much value the car keeps after five years (40% by default). At the end of the comparison window the calculator estimates what the car is worth, subtracts what you still owe, and credits you the equity.
Leases are priced with the same three ingredients dealers use: the negotiated price (cap cost), the residual value at lease-end, and a money factor. The residual comes from the same depreciation curve as the buy side, so the two sides can't disagree about what the car will be worth. The money factor is derived from the same rate feed (APR ÷ 2,400 — the industry conversion). Add the acquisition and disposition fees and, if you drive more than the mileage allowance, the overage at the fee you set.
Most comparisons stop at the payment. This one estimates tires and brakes over each term from your annual mileage — on the buy side you pay for them; on the lease side you often turn the car in before the second set. It also flags excess-mileage charges before they surprise you, and reminds you that extra miles bought up front usually cost less than the per-mile penalty at turn-in.
Manufacturer lease specials with subsidized money factors or inflated residuals can beat this math; a rough trade-in or wear-and-tear bill at turn-in can wreck it. And some states tax the full vehicle price on a lease rather than the payments. Treat the result as the honest baseline, then compare a real dealer quote against it line by line.
When you'd replace the car every three years anyway, you drive under the allowance, you keep it clean, and the manufacturer is subsidizing the lease. Under those conditions leasing can be cheaper than buying and selling a three-year-old car. Change any one of them and buying usually pulls ahead.
Multiply it by 2,400 to get an APR. A money factor of .00250 is a 6% APR. If the dealer's number converts to something well above current auto-loan rates, you're paying for the convenience — ask for the buy rate.
A cap cost reduction lowers the payment, but if the car is totaled or stolen in month two, that money is usually gone. Most people are better off with a small drive-off amount and a slightly higher payment.
Keeping it is usually the cheapest option of all — the paid-off-vs-new guide puts real repair numbers against a new-car payment by vehicle age.
Last reviewed September 2026. Read our methodology for every source and assumption, and the calculator disclaimers for what these estimates are and aren't.