How do I calculate fuel cost for a journey?

Divide the distance by your MPG to get gallons needed, multiply by 4.546 to convert to litres, then multiply by the fuel price per litre. For example, 100 miles at 40 mpg = 2.5 gallons = 11.37 litres. At 145p/litre that costs £16.48.

Should I use my real MPG or the manufacturer figure?

Always use your real-world MPG for accurate cost estimates. Manufacturer WLTP figures are typically 10-20% higher than real-world consumption. Use our MPG Calculator to find your actual figure.

What is a typical fuel price in the UK?

As of 2025, typical UK fuel prices are around 140-155p per litre for unleaded petrol and 145-160p per litre for diesel. Prices vary significantly by region and retailer. Supermarket fuel stations are typically the cheapest.

Does driving speed affect fuel cost?

Yes, significantly. Fuel consumption increases sharply above 60 mph due to aerodynamic drag. Driving at 80 mph uses roughly 25% more fuel than driving at 60 mph. The most efficient speed for most cars is between 45-55 mph.

How can I find the cheapest fuel near me?

Use apps like PetrolPrices.com, Waze, or Google Maps to compare local fuel prices. Supermarket fuel stations (Asda, Tesco, Sainsburys, Morrisons) are typically 3-5p per litre cheaper than branded stations. Loyalty cards and cashback credit cards offer additional savings.

CarCalcs

Fuel Cost Calculator

Work out the fuel cost for any journey based on distance, MPG, and fuel price.

Journey Distance

Your MPG (UK)

Use your real-world MPG, not the manufacturer figure

Fuel Price

How We Calculate This

The calculator works out how many litres of fuel your journey requires, then multiplies by the price per litre to give the total cost.

The Formula

Gallons needed = Distance (miles) / MPG
Litres needed = Gallons x 4.54609
Total cost = Litres x Price per litre
Cost per mile = Total cost / Distance

Frequently Asked Questions

Related Calculators

MPG Calculator

Calculate your car's miles per gallon from distance and fuel used.

Journey Fuel Calculator

Calculate how much fuel you need for a specific journey.

Litres Per 100km Calculator

Convert your fuel consumption to the European litres per 100km standard.

Fuel Tank Range Calculator

Find out how far you can drive on a full tank of fuel.

Annual Fuel Cost Calculator

Estimate your total yearly fuel spending based on mileage and consumption.

Last updated: February 2026

All calculations are estimates. Actual figures may vary based on driving conditions, vehicle specifications, and other factors.