Fuel Cost Calculator

Find out exactly how much any journey will cost you in fuel.

Fuel type:

Journey Distance

miles

Your Car's MPG

MPG

Don't know your MPG? Calculate it here

Fuel Price (auto-filled)

p/L

Round trip:

Trips per week: for annual cost

Enter your journey details above to calculate fuel cost

How to use this calculator

Enter your journey distance

Type in the one-way distance in miles, then toggle "Round trip" if you're calculating a return journey.

Enter your car's MPG

Use your car's real-world MPG figure for the most accurate result. Not sure? Use our MPG calculator to measure it first.

Check the fuel price

The fuel price is pre-filled with the latest UK average. You can edit it to match your local forecourt price. See current UK fuel prices.

Calculate your annual commute cost (optional)

Enter how many times per week you make this trip and we'll show you the projected annual fuel spend.

How is Journey Fuel Cost Calculated?

The formula is straightforward:

Divide your journey distance (miles) by your MPG to get gallons used
Multiply gallons by 4.54609 to convert to litres (UK Imperial gallon)
Multiply litres by the price per litre (in pence, then divide by 100 to get £) for your total fuel cost

For example: a 100-mile journey in a car doing 45 MPG, with petrol at 140p/litre:

100 ÷ 45 = 2.22 gallons
2.22 × 4.546 = 10.1 litres
10.1 × £1.40 = £14.14

What's a Typical Cost Per Mile?

For a petrol car at current UK fuel prices, the fuel cost per mile typically ranges from:

10–13p per mile for efficient small cars and hybrids (50+ MPG)
14–18p per mile for average family cars (35–45 MPG)
19–25p+ per mile for larger or older cars with lower MPG

These are fuel-only costs — they don't include insurance, road tax, or depreciation. Want to work on reducing your cost per mile? Our MPG improvement guide covers the most effective ways to stretch every gallon further.

How to Reduce Your Fuel Costs

The two levers are your MPG and the fuel price you pay. Improving your MPG has a lasting effect, while shopping around for cheaper fuel is a quick win.

Supermarket forecourts (Tesco, Asda, Sainsbury's) are consistently 3–8p/litre cheaper than branded stations
Avoiding motorway services can save 10–15p/litre
Maintaining correct tyre pressure can improve real-world MPG by 1–3%
Smooth acceleration and anticipating traffic lights can improve MPG by up to 10%

See current UK fuel price trends or read our full guide on how to improve your MPG.

Frequently Asked Questions

How do I find out my car's MPG?

The most accurate method is to fill your tank, reset your trip odometer, drive normally until you need fuel again, then fill up again and note the miles driven and litres added. Use our MPG calculator to do the maths. Your car's handbook will also list an official figure, though real-world MPG is typically 15–25% lower.

Why does the calculator use pence per litre?

Fuel in the UK is sold by the litre at the pump, so pence per litre is the standard unit. The calculator automatically converts this to a cost-per-gallon figure internally when calculating how much fuel your journey needs.

What is a good MPG for a UK car?

For a petrol car, 40–50 MPG is considered good. Hybrids and small diesels can achieve 55–65 MPG. Anything below 30 MPG is considered poor for modern cars. See our full guide on what is a good MPG for a detailed breakdown by car type.

Does the calculator work for diesel cars?

Yes — select "Diesel" at the top and the fuel price will automatically update to the latest UK diesel average. Diesel is typically priced a few pence per litre higher than petrol, though diesel cars usually achieve better MPG, which can offset the higher cost per litre.