Since September 2021, E10 petrol has been the standard at UK forecourts. But what exactly is E10, how does it differ from E5, and which one should you be putting in your car? Here's everything you need to know.
What Do E10 and E5 Mean?
The 'E' stands for ethanol, and the number indicates the percentage of ethanol blended with the petrol:
E10 Petrol
Contains up to 10% renewable ethanol
- Standard petrol at most pumps
- Typically labelled as "Unleaded" or "E10"
- Usually the cheaper option
- Green-coloured pump handle
E5 Petrol
Contains up to 5% renewable ethanol
- Available as "Super Unleaded" (97+ octane)
- Required for some older vehicles
- Typically 10-15p more per litre
- Often premium branded fuel
Why Did the UK Switch to E10?
The switch to E10 is part of the UK government's efforts to reduce carbon emissions. Ethanol is produced from renewable sources like crops and agricultural waste, making it a greener alternative to pure petrol.
The government estimates that introducing E10 will reduce CO2 emissions from transport by 750,000 tonnes per year – equivalent to taking 350,000 cars off the road.
Is Your Car Compatible with E10?
The good news is that approximately 95% of petrol cars on UK roads are compatible with E10. Generally, if your car was built after 2011, it should be fine with E10.
However, some vehicles are not compatible, including:
- Classic and older vehicles (generally pre-2002)
- Some mopeds and motorcycles
- Certain models from specific manufacturers up to 2011
Important
Using E10 in an incompatible vehicle can damage the fuel system, engine, and other components. If you're unsure, check your vehicle handbook or use the government's E10 compatibility checker.
Does E10 Affect Fuel Economy?
Ethanol contains less energy than pure petrol, which means E10 can reduce fuel economy slightly compared to E5. Most drivers report a reduction of around 1-2%, though some experience up to 3%.
In practical terms, if you typically get 40 miles per gallon, you might get 39-39.5 mpg with E10. Whether this matters depends on the price difference – if E10 is 10p cheaper per litre, you're still saving money overall despite the slightly lower mpg.
Which Should You Choose?
For most drivers with compatible vehicles, E10 is the sensible choice. It's cheaper, more widely available, and better for the environment. The slight reduction in fuel economy is typically offset by the lower price.
You should choose E5 (Super Unleaded) if:
- Your vehicle isn't compatible with E10
- You have a high-performance car that benefits from higher octane fuel
- You're storing a vehicle for an extended period (E5 has a longer shelf life)
- You have garden equipment or older machinery that isn't E10 compatible
Pro Tip
If you accidentally put E10 in an incompatible vehicle once, don't panic. A single tank is unlikely to cause immediate damage. Just use E5 for your next few fill-ups to dilute it. However, don't make a habit of it.
What About Diesel?
The E10/E5 distinction only applies to petrol. Diesel vehicles are not affected by this change and should continue using standard diesel or the specific type recommended by the manufacturer.
The Bottom Line
For the vast majority of UK drivers, E10 is perfectly suitable and represents the best value. Check your vehicle's compatibility, and if you're good to go, fill up with E10 and enjoy the savings. Use Fuelwise to find the cheapest E10 prices in your area.