How do I calculate the fuel cost of a journey?

Enter your vehicle's MPG (miles per gallon), the journey distance in miles, and the current fuel price in pence per litre. Our calculator instantly shows the total fuel cost for your trip. You can also calculate annual running costs by entering your average yearly mileage.

What is the average MPG for a UK car?

The official WLTP figure for a typical modern petrol car in the UK is around 45–55 MPG. In real-world driving conditions, most cars achieve 10–20% less than the official figure. Diesel cars typically achieve 50–65 MPG officially. Older vehicles often return 30–40 MPG.

How do I calculate MPG for an electric car?

Electric vehicles don't use MPG. Instead, select the EV option in our calculator and enter your car's efficiency in miles per kWh (typically 3–4 miles/kWh for most EVs) and your electricity tariff in pence per kWh. The average home electricity rate in the UK is around 24–28p/kWh.

What is the current price of petrol in the UK?

UK petrol prices fluctuate regularly. As of 2025, the average price is approximately 140–150p per litre for unleaded petrol and 145–155p per litre for diesel. You can check the latest prices at a forecourt near you using apps like Fuel Prices UK or PetrolPrices.com.

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Free Fuel Cost Calculator Journey & Annual Running Cost

Work out the cost of any journey or your car's annual fuel bill. Enter your car's MPG, distance and the current fuel price — instant results.

Fuel Type

Journey Distance

Annual Mileage

Journey Cost

Annual Fuel Cost

Cost per Mile

Monthly Fuel Cost

Free, No Sign-Up

Instant Calculation

Petrol, Diesel & EV

How to Use This Calculator

Finding Your MPG

Use the official WLTP figure from your vehicle brochure as a starting point. For real-world accuracy, reduce by 10–20% — most cars achieve less than the official figure in everyday driving.

You can also check your trip computer if your car has one, or calculate it manually: fill the tank, drive a known distance, then fill again and divide the miles by the litres used × 4.546.

Current UK Fuel Prices

Petrol (average)~148p/litre
Diesel (average)~155p/litre
Home electricity (day)~24–25p/kWh
Off-peak / overnight EV~7–10p/kWh

Prices updated May 2026. Check RAC Fuel Watch for live prices.

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