How the charge works
A lease sets a total mileage for the term. A 36-month lease with 8,000 miles a year, for example, carries a total allowance of 24,000 miles. The funder bases its monthly rental on how much value the car is expected to lose over that distance.
At the end of the lease the funder records the odometer reading. Any miles above the allowance are billed at the excess mileage rate in your agreement, expressed in pence per mile. The charge is simple arithmetic: miles over multiplied by the rate.
Nothing is charged while you are within the allowance, and there is no annual check. Some funders send reminders, but the bill only arrives at handback, which is why it can come as a surprise.
On a business contract the same rule applies, although VAT treatment differs. Check whether the stated rate includes VAT, because a rate quoted excluding VAT will be higher on your invoice if you cannot reclaim it.
What the pence-per-mile rate depends on
The rate reflects the funder's estimate of how much extra mileage reduces the car's resale value. A small city car loses a few pence of value per extra mile, while a large premium SUV loses considerably more. That is why a hatchback might carry a rate in single digits, while an executive saloon or large SUV can be well into double digits.
Rates are set per car and per funder, not by the industry, and they are written in the quotation and agreement. Compare the rate, not just the monthly rental, because a lower rental with a high excess rate can end up costing more for a high-mileage driver.
The excess mileage calculator lets you enter your allowance, the rate and your actual or expected mileage to see the likely charge before you reach the end of the term.
Worked examples in pence per mile
The examples below are illustrative. They show how the arithmetic scales, using round rates and mileages rather than quoted deal prices.
The pattern is clear: the rate multiplies quickly. A few thousand miles over is manageable on a low-rate car and painful on a high-rate one, so it is worth understanding both numbers.
| Allowance over the term | Actual mileage | Miles over | Rate | Charge |
|---|---|---|---|---|
| 24,000 | 26,000 | 2,000 | 6p a mile | £120 |
| 24,000 | 26,000 | 2,000 | 12p a mile | £240 |
| 30,000 | 34,500 | 4,500 | 8p a mile | £360 |
| 30,000 | 34,500 | 4,500 | 15p a mile | £675 |
| 45,000 | 50,000 | 5,000 | 10p a mile | £500 |
| 45,000 | 50,000 | 5,000 | 20p a mile | £1,000 |
Choosing the right allowance
Start from your current annual mileage, which you can find in the last two MOT certificates or from a service record. Add the journeys you expect to change, such as a new commute, a house move or regular long trips, and think about how long you will keep the car.
Most funders let you add miles at the start in blocks of 1,000 or 2,000 per year, and the cost per extra mile bought upfront is usually lower than the excess rate at the end. If you are on the edge, it is sensible to choose the higher band, but do not pick a much bigger allowance than you need because the extra cost is built into every monthly rental.
A useful rule is to aim for an allowance 5 to 10 per cent above your honest estimate. That gives a buffer for unplanned trips while keeping rentals sensible. Remember that business use, holidays and visits to family often push mileage up more than expected.
- Check MOT history for the car you currently drive to see real annual mileage
- List known changes such as a new job, school run or moving house
- Add a buffer of roughly 5 to 10 per cent
- Compare the excess rate between quotes as well as the monthly rental
- Check how many miles you would need to be over before the charge becomes larger than a higher allowance
Changing the allowance during the contract
If your driving changes, contact the funder as soon as you notice, ideally by the midpoint of the term. Many funders will agree to a revised allowance, which typically means a new monthly rental calculated over the remaining months. The amount depends on the car's current value and the revised mileage.
Some contracts allow only one change, or require a minimum remaining term, and a few do not allow changes at all. If you are well ahead of your allowance, the cost of adding miles mid-term can still be lower than paying the excess rate at the end, so ask for a written figure and compare.
If you drive less than expected, some funders will reduce the allowance and rental on request, but this is a discretionary offer. A refund for unused miles is rare, and most agreements treat the allowance as a ceiling and not a credit.
Tracking your mileage and avoiding the surprise
The simplest control is a quarterly check of the odometer against your pro-rata allowance. Divide the total allowance by the number of months and multiply by the months elapsed. If you are above that line, you have time to adjust your driving, to ask the funder to revise the contract or to budget for the excess.
Business mileage deserves a separate look. If you use your own lease car for work, a reimbursement from your employer at HMRC's approved mileage rate may help offset costs, which you can estimate with the business mileage calculator. It does not change the excess rate on the lease, though.
Finally, keep an eye on how the miles are recorded. The charge is based on the odometer reading at collection, not on your own records, so photograph it. If a mileage reading looks wrong, challenge it promptly with evidence such as the previous MOT figure.
Questions to ask before you sign
The excess mileage rate is one of the few costs in a lease that you can read in advance, yet it is easy to overlook next to the monthly rental. Ask for it in writing before you commit, and ask a few follow-up questions so there are no surprises at handback.
Also ask what happens to the allowance if the contract is extended. Many funders pro-rate it, so a three-month extension on a 24,000-mile, 36-month agreement would add about 2,000 miles, but the rate for extra miles can change in an extension.
- What is the excess mileage rate in pence per mile, and is it fixed for the whole term?
- Is there any tolerance, for example a few hundred miles, before charges apply?
- Can the allowance be changed mid-term, how often, and how is the new rental worked out?
- Is the charge shown including or excluding VAT on a business lease, and can VAT be reclaimed?
- What does the price per extra 1,000 miles bought upfront compare with the excess rate?
- Does the allowance relate to the full term or to each year, and is there a yearly check?
A longer worked example: choosing between bands
Imagine you drive about 9,500 miles a year and are choosing between 8,000 and 10,000 miles a year on a 36-month lease. The first allowance is 24,000 miles and the second 30,000 miles. Over three years you would drive about 28,500 miles, which is 4,500 over the lower allowance.
At an excess rate of 8 pence a mile, the lower band would produce a final bill of £360. If the 10,000-mile band adds, say, £6 to the monthly rental over 36 months, that is £216 in total, which is cheaper than the excess charge and removes the risk of a larger bill. If the added rental were £14 a month, the total would be £504 and the lower band with an expected excess charge would be better value, provided your mileage really would not grow.
The break-even logic is the same each time. Work out the total extra rental for the higher band, then compare it with the likely excess charge on the lower band, and add a buffer for the chance that you drive more. Because the excess rate is usually higher than the effective upfront price per mile, buying slightly too many miles is normally a cheaper mistake than buying too few.
For a business user with high variation, the same exercise can be run at three mileages: your low, expected and high estimates. If the higher band is cheaper in two of the three cases, it is generally the safer pick. The true cost of leasing tool helps compare the total cost under different assumptions.
Other ways to reduce the bill
A few practical choices can lower your exposure. Shorter terms with the same annual mileage carry a lower total, so a 24-month lease has a smaller risk of drift than a 48-month one. Combining a modest allowance with a planned early return or swap is another option, though early termination charges are usually high.
If you only need a car for a short period, alternatives such as a short-term car lease or a car subscription often have simpler mileage rules. Some include generous allowances or unlimited miles, although other costs and conditions differ, so compare them on the full terms.