Fuel cost calculator for trips and jobs
Work out the fuel a journey uses and what it costs, per trip, per week and per year, from your own mpg and today's pump price. Free to use, no account, and your figures stay on your device.
- Uses UK gallons, so your mpg is right
- Per trip, per week and per year
- HMRC 2026/27 mileage claim alongside
Enter the distance, your mpg and the price per litre on today's pump.
The working
| Litres: 30 miles ÷ 35mpg × 4.54609 | 3.9 L |
|---|---|
| × 199p a litre | £7.75 |
| Fuel cost per mile | 25.8p |
| HMRC rate per job (55p a mile) | £16.50 |
HMRC's rate for cars and vans is 55p a mile for the first 10,000 business miles in the tax year, then 25p (from 6 April 2026). It is meant to cover all running costs, not just fuel. Price travel into your quotes: it is a real cost of every job.
Fuel cost of a journey: the sum
Divide the miles by your mpg to get gallons, multiply by 4.54609 to turn UK gallons into litres, then multiply by the price per litre. That is the cost of the trip. Times it by your jobs a week for the weekly figure, then by your working weeks a year for the yearly one. That box starts at 46, so change it to match the weeks you actually work.
That 4.54609 is the imperial gallon as the Weights and Measures Act 1985 defined it, and the figure still given in the NIST conversion tables. If you enter kilometres, the calculator divides by 1.609344 to get miles first.
The calculator opens on this example: a heating engineer whose jobs average 15 miles from the yard, in a diesel van that does 35mpg, with diesel at 199p a litre.
- Miles per job: 15 each way, there and back, so 30 miles.
- Fuel per job: 30 ÷ 35 = 0.857 gallons × 4.54609 = 3.90 litres.
- Cost per job: 3.90 litres × £1.99 = £7.75.
- Per week: 8 jobs is 240 miles and 31.17 litres, so £62.03.
- Per year: 46 working weeks is 11,040 miles and 1,433.97 litres, so £2,853.59.
- Cost per mile in fuel: 199p × 4.54609 ÷ 35 = 25.8p.
Getting the mpg and the price right
The answer is only as good as the two numbers you put in, and both are easy to get wrong. Use your real mpg and the price you actually pay, not the brochure figure or a national headline.
Your real mpg
Fill the tank to the brim and zero the trip meter. At the next fill, divide the miles by the litres you put in, then multiply by 4.54609. A loaded van in town will be well below its official figure, so measure it doing your normal work.
UK gallons, not US
A US gallon is only 3.785412 litres. Put a UK mpg figure into a calculator built on US gallons and it works out about a sixth too few litres, so the cost comes out too low. This calculator uses the UK gallon.
Today's price
There are no live prices here: type in what you paid. For a national average, the government's weekly road fuel prices put diesel at 199.33p and petrol at 174.57p a litre in the week of 19 October 2026.
HMRC mileage rates for 2026/27
In 2026/27, the tax year that began on 6 April 2026, HMRC's rate for cars and vans is 55p a mile for the first 10,000 business miles and 25p a mile after that. Before 6 April 2026 the first rate was 45p, which many websites still show. The calculator puts the HMRC figure next to your real fuel cost.
Sole traders and partnerships can use these as simplified expenses: a flat rate per business mile instead of the actual costs of buying and running the vehicle, such as insurance, repairs, servicing and fuel. Vans count, as goods vehicles. You cannot use it for a vehicle you have already claimed capital allowances on, and once you use it for a vehicle you must keep using it for that vehicle. Parking and other travel, such as train fares, can be claimed on top.
Employees and company directors using their own car or van can be paid the same approved mileage rates by the employer without tax. Limited companies cannot use simplified expenses. A company car is different again: HMRC publishes separate advisory fuel rates, reviewed every quarter.
In the example, 11,040 business miles works out at 10,000 × 55p plus 1,040 × 25p, which is £5,760, against £2,853.59 of fuel. The gap is not a profit: the flat rate is meant to cover the whole van, and fuel is only part of it.
Only business miles count. gov.uk says you cannot claim travel between home and work, so whether your drive to each job counts depends on where your business is based. Ask your accountant if you are not sure. Treat the HMRC figure as a guide, not tax advice.
How to price travel into a quote
Fuel is usually the smallest part of what travel costs you. The bigger part is time behind the wheel that nobody is paying for, and then the wear on the van. Price all three, or a job across the county quietly pays less than one round the corner.
Take a four-day job 40 miles away, in the same 35mpg van at 199p a litre.
- Fuel: 80 miles a day uses 10.39 litres, £20.68 a day, so £82.71 over the four days.
- Time: an hour and a half a day on the road at a £40 hourly rate is £60 a day, so £240.
- Together: £322.71 of travel before the van's wear and tear. At HMRC's 55p, the 320 miles come to £176, a rough guide to the whole running cost of the van.
Build it into the rate
If most jobs are local, an average travel cost per job can sit inside your day rate. Put a year's fuel figure from this page into the fuel box there.
Charge it as a line
For jobs well outside your usual patch, add travel as its own line on the quote, or charge by zone or by mile. Customers accept a clear travel line more easily than a mystery uplift.
Set a minimum
A small job a long drive away can cost more in fuel and time than it earns. A minimum charge, or a radius you will not quote outside, stops that happening by accident.
What the calculator leaves out
It is a fuel calculator, so it does not plan the route or measure the distance. Take the mileage from your sat nav or a map and type it in. It also assumes the same mpg for every mile, when stop-start town driving, a full load or a roof rack will burn more.
- Tolls, congestion and clean air zone charges are not included. Add them yourself where they apply.
- Electric vans and cars are not covered: they are priced in pence per kWh, not per litre.
- Prices change weekly. Re-run your yearly figure when the pump price moves.
- Business miles are for you and your accountant to settle. Which of your miles count as business miles, and which method suits you, is a question for your accountant.
Common questions
How do I calculate the fuel cost of a journey?
Divide the miles by your mpg to get gallons, multiply by 4.54609 for litres, then multiply by the price per litre. A 30-mile round trip at 35mpg and 199p a litre uses 3.90 litres and costs £7.75.
How many litres are in a UK gallon?
4.54609 litres. A US gallon is smaller, at 3.785412 litres, so check that any mpg figure or calculator you use is in UK gallons.
What is the HMRC mileage rate for 2026/27?
For cars and vans, 55p a mile for the first 10,000 business miles in the tax year and 25p a mile after that. It rose from 45p on 6 April 2026. Motorcycles are 24p a mile (GOV.UK).
Can I claim fuel and the mileage rate for the same van?
No. The flat rate replaces the actual costs of running the vehicle, fuel included. You choose one method per vehicle. You can still claim parking on top of the flat rate.
Can sole traders claim mileage for a van?
Yes. Simplified expenses cover cars and goods vehicles such as vans, as long as you have not claimed capital allowances on that van. If you bought the van and claimed the cost against your profits, you claim its actual running costs instead.
How do I work out my van's mpg?
Brim the tank and reset the trip meter. Next time you fill up, divide the miles driven by the litres you put in, then multiply by 4.54609. Do it over a normal working week, loaded as you usually are.
How much should I charge for travel on a quote?
Enough to cover the fuel, your time driving and the wear on the van. Work out the fuel here, price the time at your hourly rate, and either build an average into your rates or add a travel line for jobs outside your usual area.
Does the calculator use live fuel prices?
No. Prices differ between forecourts and change every week, so you type in the price you pay. The government publishes a weekly national average for petrol and diesel if you want a benchmark.
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