E10 or super unleaded (E5)? Which petrol should you buy?
E10 has been standard unleaded since 2021. When super unleaded E5 is worth paying extra for, which cars should avoid E10 and how to check yours.
Since September 2021 the standard unleaded petrol in the UK is E10, which contains up to 10% bioethanol. The previous standard, E5 (up to 5% ethanol), is still sold as super unleaded, usually at 97–99 octane (RON).
Does your car need E5?
Almost all petrol cars built since 2011 are compatible with E10. Some older cars, classic cars, many mopeds and some motorcycles are not. Check your registration on the GOV.UK vehicle checker before you buy.
Is super unleaded worth the extra?
Super unleaded usually costs 10–15p a litre more. Unless your manufacturer specifies high octane (some performance cars do) or your vehicle is not E10-compatible, you are unlikely to save money. Ethanol holds slightly less energy than petrol, so E10 can return marginally fewer miles per gallon, but the difference is normally small and far less than the price gap.
Compare prices
See the live average for unleaded E10 and super unleaded, or check the cheapest stations.
Frequently asked questions
Can I put E10 in any petrol car?
Most cars made since 2011 can. Older and classic cars may not – use the GOV.UK checker with your registration number.
What if I put E10 in a car that needs E5?
One tank is unlikely to cause immediate damage, but fill up with E5 next time and keep using it. Repeated use of E10 in an incompatible engine can damage seals and fuel-system parts.