What is the average petrol price in the UK? (May 2026)
As of May 2026, the average petrol price in the UK is approximately 157p per litre, while diesel averages 170p per litre. Prices vary by region and retailer — supermarket forecourts are typically 3–5p/litre cheaper than motorway services. The RAC Fuel Watch and PetrolPrices.com track live prices across the UK.
How to calculate your car's MPG
To measure your real-world MPG accurately: brim your fuel tank, reset your trip counter, drive normally, then brim the tank again. Divide the miles driven by the litres used, then multiply by 4.546 to convert to UK MPG. Most modern cars also display live fuel economy on the dashboard.
Be aware that manufacturer MPG figures (WLTP) are measured under test conditions and are typically 10–20% higher than real-world driving.
Petrol vs diesel vs electric: which is cheapest per mile in 2026?
At current UK average prices (May 2026), home-charging electric vehicles cost approximately 7–10p per mile, compared to around 20–25p per mile for a petrol car averaging 35mpg and 17–20p per mile for diesel. Public charging narrows this gap significantly — rapid charging at motorway services can cost as much as 75p/kWh, making EVs comparable to diesel per mile.
Tips to reduce your fuel costs
- Keep tyres inflated — under-inflation increases rolling resistance and fuel consumption by up to 3%
- Remove roof boxes and racks when not in use — aerodynamic drag significantly increases fuel use at motorway speeds
- Accelerate smoothly — harsh acceleration uses significantly more fuel than gradual acceleration
- Use cruise control on motorways to maintain a steady speed
- Shop around for fuel — use apps like PetrolPrices.com to find the cheapest nearby forecourt
- Consider cashback credit cards that offer rewards on fuel purchases