Lease Mileage Calculator (projected miles or km, overage & excess charge)

Understanding the lease mileage calculator — concept and principle

A car lease includes a fixed distance allowance per year. At turn-in you pay a fee for every mile or kilometre above the total. This calculator projects where your current driving pace will leave you at the end of the lease, what the overage could cost and how much you can drive per month from now on to stay within the allowance.

At 1,194 a month the car would reach 43,000 by turn-in, 7,000 over the 36,000 allowance.

How it is calculated

Total allowance = yearly allowance × lease months ÷ 12.
Your pace per month = distance so far ÷ months elapsed.
Projected distance at lease end = pace × lease months.
Projected excess = projected distance − total allowance (never below zero); projected charge = excess × fee per unit.
Over or under so far = distance driven − yearly allowance × months elapsed ÷ 12.
Maximum per month from now = (total allowance − distance so far) ÷ months remaining.

The principle

The allowance is spread evenly over the lease, so at any point you can compare what you have used with what you have "earned". Projecting forward assumes you keep driving at the same average pace. The overage charge is linear: every unit over costs the same fee. That makes the estimate simple, and it also shows how quickly a small monthly excess adds up over a three-year lease.

Worked example

Default inputs: 12,000 per year, 36-month lease, 18 months elapsed, 21,500 driven, 0.25 USD per unit over.

Total allowance = 12,000 × 36 ÷ 12 = 36,000.
Pace = 21,500 ÷ 18 ≈ 1,194 per month.
Projected distance = 21,500 ÷ 18 × 36 = 43,000.
Projected excess = 43,000 − 36,000 = 7,000; charge = 7,000 × 0.25 = 1,750 USD.
Over so far = 21,500 − 12,000 × 18 ÷ 12 = 3,500.
To stay within: (36,000 − 21,500) ÷ 18 ≈ 806 per month for the rest of the lease.

Each point is the calculator re-run with only “Months since the lease started” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Months since the lease started	Projected excess charge
4.5	$34,000
9	$12,500
13.5	$5,333
18	$1,750
22.5	$0
27	$0
36	$0

How to read the result

A projected charge of zero means you are on track. If you are over, compare three options: drive less, buy extra miles from the leasing company in advance (often cheaper per unit than the turn-in fee), or plan to pay the fee. If you will buy the car at the end, excess mileage fees usually do not apply, but check your contract.

Common mistakes

Using the odometer reading without subtracting the miles on the car at delivery.
Assuming the pace will stay the same when a long trip or job change is coming.
Forgetting that some leases charge a different fee per unit.
Ignoring wear-and-tear charges, which are separate from mileage.

Keep in mind: The projection assumes a steady driving pace and a single fee per unit. Your lease contract sets the actual terms. This is not financial advice.

Frequently asked questions

How much does going over lease miles cost?

Fees are set in the contract; many US leases charge somewhere in the range of 0.15 to 0.30 USD per mile. Use your own contract figure.

Can I buy extra miles during the lease?

Many lessors allow it, often at a lower rate than the turn-in fee. Ask before the lease ends.

Do excess miles matter if I buy the car?

Usually not, because you are buying the car at the agreed residual price, but read your contract.

Sources: Federal Reserve Board, Keys to Vehicle Leasing (consumer guide) · Consumer Financial Protection Bureau, consumer guidance on auto leases

Checked 9 Nov 2026. Straight-line projection of distance driven and excess-distance charge = (projected − allowed) × contract fee: standard lease arithmetic (fees and allowances come from your lease contract).

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