E10 or E5: which petrol should you buy?
If your car is approved for E10, buy E10. It is the standard unleaded petrol at UK forecourts, it costs less than super unleaded, and the difference in fuel economy is too small to notice. E5 is for vehicles that are not approved for E10, mainly classic and older cars, some models from the early 2000s and some small mopeds.
What is the difference between E10 and E5?
The number is the maximum share of renewable ethanol blended into the petrol. E10 contains up to 10% ethanol and E5 contains up to 5%. Mixing in ethanol reduces the carbon dioxide produced by the fuel, which is why the government made E10 the standard grade.
At the pump, E10 is the standard 95 octane unleaded. E5 is now sold as the higher-octane "super" grade, which is 97 octane or above.
| E10 | E5 | |
|---|---|---|
| Ethanol content | Up to 10% | Up to 5% |
| Sold as | Standard unleaded (95 octane) | Super unleaded (97+ octane) |
| Price | Lower | Usually noticeably higher |
| Suits | Most petrol cars on the road | Older, classic and some early-2000s vehicles |
When did E10 become standard in the UK?
Standard petrol became E10 in Great Britain in September 2021 and in Northern Ireland in November 2022. Before that, standard unleaded was E5.
Can my car use E10?
Almost certainly, if it was built in the last 15 years. According to the government, all new cars built since 2011 are compatible with E10, and most cars and motorcycles built since the late 1990s are approved for it.
The vehicles that may not be compatible are:
- classic, cherished and older vehicles
- some specific models, particularly from the early 2000s
- some mopeds, particularly those with engines of 50cc or less
How do I check if my car is E10 compatible?
Use the government's E10 vehicle checker. It covers cars, motorcycles and mopeds, and you search by make and model.
If your vehicle isn't listed, check the owner's manual or ask the manufacturer. A garage or MOT centre can also advise. Vehicles made from 2019 onwards should have an E10 or E5 label near the filler cap, which matches the label on the pump nozzle.
What happens if I put E10 in a car that isn't compatible?
Don't panic. The government's guidance is that filling up with E10 once will not damage the engine. Fill up with E5 next time. Using E10 over a long period in a car that isn't approved for it may cause harm and is not recommended, because the higher ethanol content can affect some seals, plastics and metals used in older fuel systems.
Is E10 worse for fuel economy?
Slightly, but you are unlikely to notice. The government says you may see a reduction of around 1% in fuel economy. On a car that does 40 mpg, that is roughly the difference between 40 and 39.6 mpg.
The price gap between standard and super unleaded is usually far larger than 1%. So if your car is approved for E10, paying extra for E5 to get better economy costs you money. The UK average for E10 is 174.2p a litre right now.
Is E5 still available?
Yes. The government says E5 remains available at filling stations that sell two grades of petrol, as the super grade. Some rural, remote or very small filling stations sell only one grade, which may be either E5 or E10, so check the pump before you fill up if you need E5.
Should I put E5 in a classic car?
If your classic or older car is not on the approved list, use E5. If you store the car for long periods, ask a specialist or owners' club for advice on fuel storage too, as ethanol blends can absorb moisture over time.
Some owners of approved modern cars choose super unleaded because they believe it improves performance. That is a personal choice. If your manufacturer specifies 95 octane, the car is designed to run well on standard E10.
Find E10 and E5 prices near you
Prices for both grades vary a lot from one forecourt to the next. Search by postcode to compare standard and super unleaded at every station near you, using prices last updated at 17:30 on 16 Oct.
Sources
- GOV.UK: E10 petrol explained
- GOV.UK: Check if your vehicle can use E10 petrol
- Live prices: the UK government's Fuel Finder scheme, via Cheapest Fuel. Contains public sector information licensed under the Open Government Licence v3.0.