How to use the Fuel Cost Calculator
- 1 Enter the distance in miles.
- 2 Enter your car's mpg.
- 3 Enter the price in pence a litre.
- 4 Optionally enter journeys a month.
Worked example
A 200-mile journey in a car that does 45 mpg, with fuel at 137p a litre. The journey uses about 20.2 litres and costs about £27.68, around 13.8p a mile. For business travel, HMRC's 45p rate would pay £90.
Features
UK units
Miles, mpg (imperial gallons) and pence a litre.
Pence per mile
The real fuel cost of each mile.
HMRC comparison
45p a mile approved mileage rate.
When to use it
Road trips
Budget fuel for a long drive.
Commuting
Compare driving with the train.
Business mileage
Compare actual cost with the 45p rate.
Lift sharing
Split costs fairly.
Frequently asked questions
How do I calculate fuel cost?
Litres = miles ÷ mpg × 4.546. Cost = litres × price.
Is mpg in UK or US gallons?
UK figures use imperial gallons of 4.546 litres.
What is the HMRC mileage rate?
45p a mile for the first 10,000 business miles, 25p after that.
How can I improve mpg?
Keep tyres inflated, drive smoothly and remove roof racks.
Is diesel cheaper?
Diesel cars often do more mpg, but diesel can cost more per litre.
Where do I find my mpg?
On your car's trip computer or the manufacturer's figures.
What about electric cars?
Home charging often costs a few pence a mile.
Do fuel prices vary by area?
Yes. Supermarkets are often cheaper than motorway stations.
What is the mpg of a typical car?
Many small petrol cars achieve 45 to 55 mpg, while larger SUVs often manage 30 to 40 mpg.
How do I convert mpg to litres per 100 km?
Divide 282.5 by mpg. 45 mpg is about 6.3 L/100 km.
Can I claim fuel for work?
Employees using their own car for business can claim 45p a mile tax-free, and get tax relief on any shortfall.
Does cold weather increase fuel use?
Yes. Short trips in winter can raise fuel use noticeably.
What about road tax?
Vehicle Excise Duty is a separate yearly cost not included here.
How do I split costs for a lift share?
Divide the journey cost by the number of people. Charging passengers only for fuel usually does not affect your insurance.
Is it cheaper to drive or take the train?
For one person, the train can be cheaper on long journeys once parking and wear are included. For several people sharing a car, driving is often cheaper.
How much does motorway speed affect mpg?
Driving at 70 mph instead of 80 mph can save around 10% of fuel.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Reviewed by ToolsUnlocked Team · Last updated