Fuel Cost Calculator

Compare petrol, diesel and EV running costs. UK prices for 2026.

Distance

miles

Frequency

Vehicle 1

Fuel Type

Fuel Efficiency

MPG

Fuel Price

/litre

Compare with a second vehicle

Vehicle 2

Fuel Type

Efficiency

mi/kWh

Energy Price

/kWh

Per journey

Fuel used 3.41 litres

Journey cost £4.94

Comparison

Vehicle 1 (Petrol) £1,284

Vehicle 2 (EV) £545

You save £739 per year with Vehicle 2

16p

per mile

Fuel: £4.94

Typical other costs: £3.60

Fuel Cost Per Journey

Distance	Petrol (40 MPG)	Diesel (45 MPG)	EV (3.5 mi/kWh)

How to Calculate Fuel Costs

Working out the cost of a journey depends on your vehicle's fuel efficiency, the type of fuel it uses, and the current price you pay per litre or per kWh. Here is how the maths works for each fuel type.

Petrol and Diesel

Litres needed = (Distance / MPG) x 4.546 Cost = Litres x Price per litre

First convert miles to litres by dividing your journey distance by your MPG figure, then multiplying by 4.546 (the number of litres in a UK gallon). Multiply the litres used by the price per litre to get the cost.

Electric Vehicles

kWh needed = Distance / Miles per kWh Cost = kWh x Price per kWh

For EVs, divide the distance by your vehicle's efficiency rating (measured in miles per kWh). Then multiply the kWh consumed by the electricity price. Home charging typically costs around 24.5p per kWh on a standard tariff, while public rapid chargers can cost 50-80p per kWh.

Annual Costs

To calculate annual fuel spending, multiply the single journey cost by how often you make the trip. A daily commute across 260 working days, a weekly trip across 52 weeks, or a monthly trip across 12 months. The average UK driver covers around 7,400 miles per year.

Real-World MPG

Manufacturer MPG figures are tested under controlled conditions. Real-world fuel efficiency is typically 10-20% lower due to traffic, weather, driving style, and vehicle load. If your car is rated at 50 MPG, expect closer to 40-45 MPG in daily driving.

Fuel Cost FAQs

How much is UK fuel duty in 2026?

UK fuel duty is currently 52.95p per litre for both petrol and diesel. On top of this, VAT at 20% is charged on the total price including fuel duty, meaning tax makes up a significant portion of what you pay at the pump.

Is it cheaper to run an electric car than a petrol car?

Yes, in most cases. Charging an EV at home costs roughly 3-5p per mile compared to 12-18p per mile for a petrol car. Even using public rapid chargers at higher rates, EVs typically cost around 7-10p per mile. Over a year of average UK driving (7,400 miles), this can save between £500 and £1,000 on fuel alone.

What does MPG mean and how is it calculated?

MPG stands for miles per gallon and measures how far a vehicle can travel on one gallon (4.546 litres) of fuel. A car rated at 40 MPG will travel 40 miles on one gallon of fuel. Real-world MPG is typically 10-20% lower than manufacturer figures, which are measured under controlled test conditions.

Related Calculators

Use our other free UK calculators to work out mileage claims, VAT on purchases, or self-employed tax.

Mileage Calculator → VAT Calculator → Self-Employed Tax →