E10 vs E5 petrol: which should you use?
Two green pumps, two prices, and a gap that adds up to several pounds a tank. Here is what the labels mean, who actually needs the dearer one, and how to check your own car in a minute.
Updated 2 October 2026 · Written by the Fuel Finder UK team
What E10 and E5 mean
The number is the most bioethanol the petrol can contain. E10 has up to 10% renewable ethanol. E5 has up to 5%. At a UK forecourt, E10 is the standard 95-octane unleaded, and E5 is the 97-octane-plus grade sold as super unleaded.
E10 became the standard grade in Great Britain in September 2021 and in Northern Ireland in November 2022. Pumps carry a round label reading E5 or E10. Diesel pumps carry a square B7 label.
What the difference costs
On 2 October 2026 the UK average was 174.8p a litre for E10 and 192.5p for super unleaded E5. That is a 17.7p gap, or about £9.70 on a 55-litre fill. The figures move daily, so check today's UK average by fuel grade and super unleaded prices by brand and area.
Which cars can use E10
Every new car built since 2011 is E10 compatible, and the Government puts the share of petrol vehicles on the road that can use it at around 95%. The ones that may not be are mostly classic and cherished cars, some models from the early 2000s, and some mopeds, especially those with engines of 50cc or under.
Do not guess. Use the Government's E10 vehicle checker, or look in the handbook or inside the fuel filler flap.
When E5 is the right choice
- Your vehicle is not E10 compatible. Keep using E5.
- Your handbook asks for 97 or 98 octane. Some performance engines are tuned for it. That is about octane, not ethanol, and super unleaded is where you get it.
- Petrol garden tools and small engines. Check the manual, because some makers ask for E5.
For an ordinary modern car, paying extra for E5 will not save you money. Government guidance says E10 may reduce fuel economy by around 1%, which is far less than the price gap.
Put the wrong one in?
If your car is compatible, you can mix E5 and E10 freely. If you put E10 in a car that should not have it, one tank should not be a major problem and it does not need draining. Just fill up with E5 next time. That is a different thing from putting petrol in a diesel car, which does need draining.
Finding the cheapest of either
Super unleaded prices vary far more between stations than standard unleaded, so it pays to compare. Filter by fuel grade and you are comparing like with like. See how each brand prices its fuel, or read how to find the cheapest petrol near you.
Quick answers
Is E10 the same as unleaded?
Yes. In the UK, E10 is the standard 95-octane unleaded petrol. E5 is the super unleaded grade.
Can I mix E5 and E10 petrol?
Yes, if your vehicle is E10 compatible. There is no need to run the tank down before switching.
Does E10 give worse mpg?
Slightly. Government guidance puts the reduction at around 1%, which you are unlikely to notice in everyday driving.
Is E5 being phased out?
No. E5 stays on sale as the super unleaded grade at filling stations that sell two grades of petrol.
For live prices near you, Fuel Finder UK lets you sort stations by price or distance and filter by fuel grade and brand.