What's the difference between E10 and E5?
The "E" number is the maximum share of renewable ethanol blended into the petrol:
| E10 | E5 | |
|---|---|---|
| Ethanol content | Up to 10% | Up to 5% |
| Usually sold as | Unleaded (standard grade) | Super unleaded |
| Octane rating | 95 RON | 97 RON or higher |
| UK average price on 25 Oct | 173.6p | 194.0p |
E10 became the standard petrol in Great Britain in September 2021 and in Northern Ireland on 1 November 2022, replacing the old E5 standard grade. Blending in more ethanol, which is made from crops, cuts the carbon dioxide emissions from petrol cars.
E5 is still sold as the "super" or premium grade at most forecourts, so drivers who need it can still buy it.
Can my car use E10?
Most likely, yes. Around 95% of petrol cars on UK roads can use E10, and all petrol cars built since 2011 are compatible.
The cars most likely to need E5 are:
- some cars built before 2011, particularly some from the early 2000s
- classic and historic vehicles
- some older mopeds, motorbikes and petrol garden machinery.
The quickest way to check is the free GOV.UK E10 checker, which covers most makes. Your owner's manual, or the inside of the fuel filler flap, may also say which fuels are approved.
What happens if I put E10 in a car that needs E5?
It isn't like putting petrol in a diesel car. Filling up with E10 by mistake won't stop your engine or need the tank draining. Just fill up with E5 next time.
Using E10 for a long time in a car that isn't designed for it can cause problems over months or years: the extra ethanol can damage some older rubber seals, plastics and metal parts in the fuel system, and the fuel can absorb water if a car stands unused for long periods.
Is E10 worse for fuel economy?
Slightly. Ethanol contains a little less energy than petrol, so you may see around 1% lower miles per gallon on E10 – most drivers won't notice it day to day.
Is it worth paying extra for E5 or premium petrol?
For most modern cars, no. Your car is designed to run on 95-octane E10, and today the higher-grade fuel costs around 20.4p more per litre. If you use 100 litres a month, that's about £20.41 a month extra for no benefit in an ordinary engine.
Premium fuels can help high-performance engines that are designed for higher-octane fuel; the handbook will say if your car needs or benefits from it. If it just says "95 RON" or "unleaded", standard E10 is the right choice.
How do I find the cheapest E10 near me?
Search your postcode or town on Motor Snappy to see live unleaded (E10) and super unleaded (E5) prices at forecourts near you, with the cheapest highlighted. Prices update every 30 minutes from retailers' open data.