Unleaded VS Super Unleaded, What’s The Difference?

A handy guide on petrol types, and which fuel is the best for you’re car!

When your filling up at the pumps, the names Unleaded E10 and Super Unleaded E5 sound like 2 versions of the same thing, one standard and one more premium option. And when it comes to the price thats exactly how they are positioned. But it comes down to much more than the price, with specific models of cars recommending Super Unleaded as well as keeping older cars running smoothly. 

So what actually separates Unleaded and Super Unleaded, which one does your car need and where can you buy it? 

What Do E10 And E5 Actually Mean?

The E numbers that you find on petrol pumps refer to the percentage of bioethanol content blended into the petrol. Since September 2021 Unleaded E10 has been the standard petrol in the UK. With E5 now found in Super Unleaded. When bioethanol is added to the fuel it helps to reduce greenhouse gas emissions and is a renewable fuel source. 

E10 Contains 10% Bioethanol and 90% unleaded petrol. Most modern petrol cars are compatible with this fuel and all cars manufactured after 2011 are approved to use it. 

E5 contains up to 5% Bioethanol and 95% unleaded petrol. Many older cars were not designed for higher Ethanol levels. This can degrade fuel lines and corrode seals and gaskets. 

The Main Difference: Octane Ratings

The key differences between Unleaded and Super Unleaded petrol is their Octane ratings. This is a measure of how well fuel copes with the heat and pressure inside of your engine. Higher octane fuels allow the engine to run more efficiently and smoothly, especially in vehicles designed for high‑performance driving.

Unleaded E10 (95 Octane)
Regular unleaded has a octane rating of 95 Designed to run on most cars this has been the standard grade of petrol that cars are designed to run.

Super Unleaded E5 (97-99 Octane)
Super unleaded has a higher octane rating of 97 to 99 depending on the brand, making it a more refined and efficient fuel. Often recommended for Performance cars, turbocharged and supercharged engines and engines with high compression ratios. Some vehicles manufacturers specifically recommend 97+ octane petrol. 

Who stocks Super Unleaded 

Creswells Garage! Find us here in Wokingham! 

Which One Should I Choose? 

Choose Regular Unleaded (E10) if:

• Your vehicle handbook confirms it’s suitable for E10
• Your car was built after 2011, as these vehicles are designed for E10
• You drive a standard petrol car used for everyday driving
• You want the most cost‑effective option
• Your engine does not require higher‑octane fuel

Regular Unleaded offers the standard octane level most modern engines are tuned for, and it’s the default choice for the majority of UK drivers.

Choose Super Unleaded (E5) if:

• Your car was built before 2011 and may not be compatible with E10
• Your manufacturer recommends or requires a higher‑octane fuel
• You drive a high‑performance or premium vehicle that benefits from smoother combustion
• You prefer E5 petrol due to its lower ethanol content
• You want potentially improved engine refinement or efficiency

Super Unleaded not only offers a higher octane for enhanced performance, but being E5, it’s also safer for older engines that aren’t designed for the higher ethanol levels found in E10.

Final Thoughts

Both fuels are safe, widely available and suitable for UK vehicles the key is understanding what your own car needs and how you drive.
At Cresswells Garage, we supply both Unleaded and Super Unleaded, so you can always choose the right option for your vehicle with confidence.