E10 vs E5 petrol: what's the difference?
What the numbers mean, whether your car can use E10, and when super unleaded is worth paying for.
E10 replaced E5 as the standard unleaded at UK pumps in September 2021 (2022 in Northern Ireland). E5 is still sold as super unleaded.
What the numbers mean
The "E" stands for ethanol; the number is the maximum percentage blended in. E10 contains up to 10% ethanol, E5 up to 5%. Ethanol is a renewable fuel made from crops, and the government estimated the switch to E10 would cut transport CO2 by around 750,000 tonnes a year.
Side by side
| E10 (unleaded) | E5 (super unleaded) | |
|---|---|---|
| Ethanol | Up to 10% | Up to 5% |
| Octane | 95 RON | 97–99 RON |
| UK average, late September 2026 | 158.9p | 175.9p |
| Compatibility | Almost all cars from 2011 | All petrol cars |
| Availability | Every petrol station | Most stations |
Is my car compatible with E10?
Almost all petrol cars built since 2011 are, and many older ones too. Cars that may not be include some models from before 2002 and some classics. Check yours with the government's E10 vehicle checker at gov.uk/check-vehicle-e10-petrol. If your car isn't compatible, use E5.
Does E10 affect fuel economy?
Slightly. Ethanol carries less energy than petrol, so expect around 1% fewer miles per tank. With E5 averaging 17p a litre more in late September 2026, E10 is still far cheaper per mile.
Is super unleaded worth it?
For most drivers, no. Higher octane only helps engines tuned for it. Buy E5 if:
- your car isn't E10-compatible
- your manufacturer specifies 97+ RON fuel
- you have a high-performance engine designed for it
Otherwise, stick with E10 and find the cheapest near you. Tanki shows both: switch between Unleaded (E10) and Super (E5) with one tap.
Questions
Can my car use E10?
Almost all petrol cars built since 2011 can, and many older ones too. Check yours with the government's E10 checker at gov.uk/check-vehicle-e10-petrol.
What if I put E10 in a car that isn't compatible?
One tank won't cause immediate damage. Fill up with E5 next time; long-term use can harm some seals and fuel-system parts in older cars.
Is super unleaded worth it?
Only if your car isn't E10-compatible or its manufacturer specifies 97+ RON fuel. Otherwise it costs more for no real benefit.