E10 vs E5 Premium Unleaded: Is it Worth the Extra Cost?

Understanding the Difference Between E10 and E5

In September 2021, E10 petrol became the standard grade of unleaded fuel in the UK, replacing the older E5 blend. The "E" stands for ethanol, and the number represents the maximum percentage of renewable ethanol in the mix. E10 contains up to 10% ethanol, while E5 contains up to 5%.

While this change was driven by environmental targets to reduce CO2 emissions, it left many drivers confused at the pump. Premium unleaded is now the only way to get E5 fuel. But is it worth paying the extra 10p to 15p per litre?

Does E5 Give You Better Mileage?

Ethanol has slightly less energy density than pure petrol. Because E10 has more ethanol, you might see a tiny reduction in fuel economy—usually around 1% to 2%. However, the massive price gap between standard E10 and premium E5 means that the tiny MPG gain from premium fuel will almost never offset the higher cost at the pump.

Is E10 Safe for My Car?

Almost all petrol vehicles built after 2011, and most since 2001, are fully compatible with E10. If you drive a modern car, there is absolutely no mechanical reason to pay extra for E5 unless you are driving a high-performance sports car that specifically requires a higher octane rating.

However, if you drive a classic car or a vehicle manufactured before 2001, the higher ethanol content in E10 can damage rubber seals and plastics in your fuel system. For these drivers, paying for premium E5 is a necessary expense.

The Verdict

For 95% of UK drivers, standard E10 is perfectly fine. The cheapest way to drive is to find the lowest E10 price near you. Use FindPetrol to compare unleaded prices across supermarkets and independent forecourts to ensure you never overpay.