Fuel Types & Quality
Super Unleaded
Is super unleaded worth it?
CheckFuelPrices Editorial
Expert Written • 4 industry sources
Super unleaded is worth it for specific vehicles, but unnecessary for most everyday cars. It offers a higher octane rating (97–99 RON vs 95 RON for standard E10) which benefits high-performance, turbocharged, or older engines that require it — but delivers little measurable gain for a typical family hatchback.
What Super Unleaded Actually Is
Higher octane rating:
Super unleaded has an octane rating of 97–99 RON, compared to 95 RON for standard E10 petrol. Higher octane fuel resists 'knocking' better under high compression.
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Lower ethanol content:
Standard E10 petrol contains up to 10% ethanol. Super unleaded (sold as E5) contains no more than 5% ethanol, which can matter for older vehicles and certain engine components.
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Additional additives:
Premium fuels typically include enhanced detergent packages designed to clean fuel injectors and combustion chambers over time.
When Super Unleaded Is Worth It
High-performance and turbocharged engines:
Cars with high-compression or turbocharged engines — such as performance variants from BMW, Audi, or Mercedes — are tuned to use higher octane fuel and will run more efficiently on super unleaded.
Older or classic vehicles:
Vehicles built before 2011 may not be fully compatible with E10 petrol. For these cars, super unleaded (E5) is the recommended fuel to avoid potential seal and rubber degradation.
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Check your handbook first:
If your manufacturer specifies 97 RON or higher, using super unleaded is not optional — it is required for correct engine operation.
When It Probably Is Not Worth It
Standard modern engines:
Most cars built after 2011 with naturally aspirated engines run on 95 RON E10 as intended. Using super unleaded will not provide a noticeable performance or economy improvement.
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The price premium:
Super unleaded typically costs 10–15p per litre more than standard E10. For a 50-litre fill-up on a car that does not need it, that is £5–£7.50 with no benefit.
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How to Make the Right Call
Check your owner's manual:
Your car's manual will state the minimum octane requirement. If it says 95 RON, standard petrol is fine. If it states 97 RON or higher, use super unleaded.
Compare prices before you fill up:
Super unleaded availability and pricing vary significantly between stations. CheckFuelPrices shows live super unleaded prices at stations near you so you can find the best deal if you do need it.
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Sources
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