Most mileage calculators stop at "here's your penalty." This one carries it through to the decision: the daily budget that would avoid the charge, what buying miles upfront saves, and whether buying out the lease beats paying the overage at all.
A lease payment is built on the difference between the car's price and its predicted value at turn-in — the residual. That residual assumes a specific mileage. Drive past it and the car is worth less than the lessor planned for, so the overage charge is their way of recovering the gap. It isn't arbitrary, which also means it's rarely forgiven.
Rates typically run $0.15 to $0.30 per mile, with $0.25 common on mainstream vehicles and higher figures on luxury models. At $0.25, being 9,000 miles over costs $2,250 — a bill that arrives all at once at the end of a lease you'd budgeted carefully.
Here's the part that generic mileage calculators skip entirely: if you buy the car at lease end, the overage charge disappears. You can't owe the lessor for reduced resale value on a car you just bought from them. The disposition fee usually vanishes too.
That changes the comparison completely for anyone significantly over. Buying out means paying the residual for a car that may be worth less than that residual because of the miles — so you might be taking on negative equity. But you're avoiding a penalty at the same time. The right test is whether the overage you dodge exceeds the equity gap you accept, and that's a calculation, not a rule of thumb.
If the buyout comes out ahead and you don't want to keep the car, buying it and selling it privately is a further step worth pricing — though it means paying sales tax on the purchase in most states.
Many lessors sell additional miles in advance at a meaningfully lower rate than the lease-end penalty — commonly $0.10–0.15 against $0.20–0.30. On 9,000 excess miles that's roughly $1,080 instead of $2,250.
Two cautions. Prepaid miles are usually non-refundable, so overbuying wastes money outright — there's no credit for unused allowance. And not every lessor offers this mid-lease; some only allow it at signing. Ask early, because the option often narrows as you approach turn-in.
The cheapest fix happens before you sign. Raising the allowance from 10,000 to 12,000 miles a year typically adds $15–25 a month; going to 15,000 adds $30–50. Over 36 months that's $540–900 or $1,080–1,800 respectively, against a potential turn-in bill several times larger.
Be honest about the estimate. A 25-mile each-way commute is about 13,000 miles a year before any weekend driving. Take your actual mileage from the past two years and add a cushion rather than hoping.