What are Premium Fuels?

Super unleaded and premium diesel, collectively premium fuel, are considered a luxury, something that makes us feel better although it doesn’t always provide a worthwhile benefit to the car with consistent use.

What is the difference between premium fuels and normal fuel?

Super unleaded is a higher octane rating than unleaded, meaning that it has a higher knock resistance. Unleaded normally has an octane rating of 95 whereas super unleaded comes in at around 98-100. This higher performance fuel will most often be noticed by those with high-performance cars and some hot hatchbacks. If you fill up with premium fuels in those cars, you’ll notice the improved throttle response, the engine will rev more freely and should deliver more power. Although these cars are built for unleaded, for longer journeys or every 1,000 miles or so, it will be worth filling up with super unleaded just to give it the extra boost and keep the engine at full potential.

Premium diesel can have a higher cetane rating than diesel, which means that it ignites quicker when it is injected into the compressed air in the engine. The higher cetane rating doesn’t often mean anything to the engine, as diesel engines are so strictly manufactured now that it might not make a difference. The one difference that using a premium diesel will have on your car is good engine clean. In the long run, using a premium diesel every 1,000 miles or before a spell of lots of long journeys will help to clean out the engine and remove any residue soot or particulates. While the initial cost may seem hefty, using this trick will save you money in the long run by extending the life of the engine and helping to reduce the need for repairs and engine maintenance.


As the components of premium fuel are more expensive to create and take longer to engineer the prices of premium fuels are higher making it more of a luxury product. The below chart shows the prices for both super unleaded and premium diesel over the last 12 years.

Is it worth it?

Unless you’ve got a sports car that is manufacturer recommended for premium fuels or need to clean out the engine then its highly unlikely that you’ll need premium fuels, in fact, some manufacturers have said that using premium fuels won’t help the engine, and you should stick to the standard. Most engines are built for standard fuels, and very few actually need premium.

It will be worth filling up the tank every now and then with premium fuels as the long-term benefit of a cleaner engine as well as a reduction in soot in a diesel will definitely help. In a petrol car, using a super unleaded after a trip abroad where the octane rating is lower than the UK will help to get your car back to normal, but for everyday use, it’s just not practical and cost-effective to use premium fuels.

Unless you’re absolutely rolling in the money, or have a high-performance car or both, then don’t use premium fuels as normal.


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