Running cost, month by month
The buy line is what owning would have cost if you sold the car that month. The lease line is cash paid to date, with fees added at turn-in.
What tips the balance
Where the money goes
Each column adds up to its total. Selling the car gives the buyer money back.
How it's calculated
The lease payment is built the standard way: depreciation (adjusted price minus residual, spread over the term) plus a finance charge (adjusted price plus residual, times the money factor). Sales tax is added to the payment and to the amount due at signing, as most states do. If you enter the payment from your quote, it is used instead.
Buying is compared over the same term: your down payment plus loan payments, plus the loan balance you’d pay off, minus what you could sell the car for. Sales tax on the full price is financed. Both sides include what the upfront cash could have earned if invested.
You can add an expected excess-wear charge and any extra insurance a lease requires. Costs that are the same either way, such as registration, fuel and routine maintenance under warranty, are left out because they cancel. The comparison assumes you keep the lease to the end. Ending a lease early usually costs much more, so get the payoff figure from the leasing company if that is likely. Keeping a bought car well past the lease term usually lowers its cost further, because the payments end.