How to Calculate Fleet Cost Per Mile: Formula and Worksheet

Fleet cost per mile is everything a vehicle costs to run in a period, divided by the business miles it drove in that period. Fuel alone is 25.2p a mile for a diesel van at 36 mpg, using the DESNZ price of 199.22p a litre for the week of 26 October 2026. Add maintenance, tyres, insurance, depreciation and lease.

What is the fleet cost per mile formula?

The formula is total cost for the period divided by miles for the same period:

Cost per mile = (fuel + maintenance + tyres + insurance + depreciation + lease) / miles driven

Pick one period and use it for every line. A full year is best, because insurance renews annually and tyres and servicing arrive in lumps. A single month can make a good vehicle look bad or a poor one look good.

Take every figure from the same place each time, for example fuel card statements, workshop invoices and the finance schedule. Decide once whether you include VAT. If your business reclaims it, leave it out of every line that carries it.

If a vehicle is on a lease that includes maintenance, the maintenance is in the lease line already. Do not count it twice. In the same way, a leased vehicle has no depreciation line, because the lease payment covers it. An owned vehicle has depreciation and may have a finance charge instead of a lease.

How do you work out the fuel part?

You work out the fuel part from your own fuel records, and use the pump price formula to check it. The fuel cost per mile formula is:

Pence per mile = pence per litre x 4.54609 / mpg

For a diesel van at 36 mpg, with the Department for Energy Security and Net Zero (DESNZ) average diesel price of 199.22p a litre for the week of 26 October 2026 (weekly road fuel prices), that is 25.2p a mile, or £5,040 over 20,000 miles. A petrol vehicle at 32 mpg and 174.07p a litre is 24.7p.

Your fuel card data is better than a national average, because it is your price and your vehicle. Fuel cost for the period divided by miles gives your real fuel line. See diesel cost per mile, petrol cost per mile and electric van cost per mile for the tables by mpg, and our fleet cost index for this week’s figure.

What does the whole-fleet worksheet look like?

It looks like one row per cost line and one column per vehicle, with your own figures in. We have not filled in averages for the non-fuel lines, because they vary too much between vehicle types and duty cycles. Fill in the blanks from your own records.

Cost line (per year)	Where the figure comes from	Your figure
Fuel (or electricity)	Fuel card or charging statements	£ ____
Maintenance and servicing	Workshop invoices, service plan	£ ____
Tyres	Tyre supplier invoices	£ ____
Insurance	Policy premium for the vehicle	£ ____
Depreciation	Purchase price less expected resale value, spread over the years you hold it	£ ____
Lease or finance	Monthly payment times 12	£ ____
Total	Sum of the lines above	£ ____
Business miles	Odometer or telematics for the same year	____
Cost per mile	Total divided by miles	____ p

Use either the depreciation line or the lease line for a vehicle, not both. If your vehicles are financed rather than leased, the finance charge sits where the lease line is, and depreciation stays.

Other costs may matter for your operation: vehicle tax, tolls, breakdown cover, congestion and clean air zone charges, washing and tracking subscriptions. Add them as extra rows with the same period and the same VAT treatment. The method does not change.

What is a worked example?

Here is the sum with letters, so you can follow the method without our numbers getting in the way. Say one van does M miles in a year. It costs F in fuel, S in servicing and repairs, T in tyres, I in insurance, D in depreciation and L in lease.

Add the six costs: F + S + T + I + D + L. Use only one of D or L if the vehicle is either owned or leased.
Divide by M.
The answer in pounds per mile times 100 is pence per mile.

Now the fuel row with real figures. A diesel van that does 20,000 miles at 36 mpg at 25.2p a mile has a fuel line of 20,000 x 0.252 = £5,040. If the other four lines for that van came to £6,000 in total, the total would be £11,040 and the cost per mile 55.2p. The £6,000 is only there to show the arithmetic. It is not an industry average and you should not use it as one.

Do the same for each vehicle, then add up for the fleet.

How do you get one cost per mile for the whole fleet?

Add all the vehicles’ total costs and divide by all the miles. Do not average the individual cost-per-mile figures. A van that did 4,000 miles with a high cost per mile would count the same as one that did 30,000 miles at a low one, and that gives a wrong picture.

Then break it down by:

Vehicle type, so you compare vans with vans and cars with cars.
Cost line, to see which one dominates. Fuel is the one that moves each week with the price. Insurance, depreciation and lease are fixed for the year.
Driver or depot, to find the outliers.

A cost per mile that you compare month by month is useful only if the miles and the cost lines are consistent. A van off the road for a month still has insurance and a lease payment, and the cost per mile should show that.

How do you check the number against HMRC’s rates?

HMRC’s approved mileage rate is not a cost per mile. It is the amount an employee can be paid tax-free for using their own car or van, 55p a mile for the first 10,000 business miles in the tax year from 6 April 2026 and 25p above that (HMRC mileage rules). It is a useful sense check next to your own whole-fleet figure, but it is a different thing. Our mileage rates tool has the current rates and a mileage claim calculator.

Do not use it to price your own fleet. The cost of your vehicles depends on the vehicles, and that is what the worksheet is for.

Frequently Asked Questions

What is the formula for cost per mile?

Total cost for the period divided by miles driven in the same period. For a fleet vehicle, the total is fuel, maintenance, tyres, insurance, depreciation or lease, and any other running costs. Use a full year if you can.

How do I calculate fuel cost per mile?

Multiply the price in pence per litre by 4.54609 and divide by miles per gallon. A diesel van at 36 mpg with diesel at 199.22p a litre (DESNZ, week of 26 October 2026) costs 25.2p a mile. Your fuel card records give a more accurate answer for your own vehicles.

Should I include depreciation and lease together?

No. A leased vehicle’s payment covers the depreciation, so counting both counts the same cost twice. Use depreciation for owned vehicles and the lease line for leased ones. If an owned vehicle is financed, add the finance charge and keep depreciation.

How do I work out the fleet average cost per mile?

Add the total cost of every vehicle and divide by the total miles. Do not average the per-vehicle cost-per-mile figures, because a low-mileage vehicle then counts as much as a high-mileage one.

Is there a cost per mile calculator?

You can build one in a spreadsheet using the worksheet above: one row per cost line, one column per vehicle, with a total and a division by miles. For the fuel line alone, our fleet cost index has a calculator that uses the latest government fuel prices.

Cut your fleet’s fuel bill

Your number is the total from the worksheet divided by your miles. For the fuel line, start from this week’s pump-price figures on the fleet cost index, then replace them with your fuel card data.

Fuel is the line you can move fastest. The Department for Transport’s fuel consumption curves (TAG data book v2.03, May 2026, source) show a diesel van uses 14.5% less fuel per mile at 60 mph than at 68 mph. How much that takes off your fleet’s cost per mile depends on the share of your miles driven above the cap. We show the method in what speed costs per mile.

AutoKontrol has made speed limiters in Britain since 1985, for vans, cars, HGVs and buses, installed nationwide: we come to you. To have your own saving worked out, book a free consultation or get a quote. If you also want vehicle tracking, TrackSpeed puts a speed limiter and GPS tracking in one device, with one installation and one subscription.