Is premium fuel worth it?

Usually not: super unleaded costs 18.0p a litre more than regular E10 unleaded at today's median prices, £9.00 on a 50-litre fill, so it would have to take a car 10.3% further on every litre just to break even. UK motoring bodies and independent tests agree that most cars gain little or nothing from premium fuel; the ones that benefit are high-performance models whose makers call for a higher octane rating.

How much more does premium fuel cost?

Super unleaded has a median of 192.9p a litre, 18.0p more than the 174.9p for regular E10 unleaded — £9.00 more on a 50-litre fill. Super unleaded is priced at 6,203 forecourts in today's figures, against 7,878 for regular E10 unleaded.

At supermarket forecourts, super unleaded is 13.2p dearer at the median (185.9p against 172.7p). At other forecourts off the motorway, super unleaded is 20.0p dearer at the median (194.9p against 174.9p).

Premium diesel has a median of 219.9p a litre, 20.0p more than the 199.9p for standard diesel — £10.00 more on a 50-litre fill. Premium diesel is priced at 4,141 forecourts in today's figures, against 7,992 for standard diesel.

At supermarket forecourts, premium diesel is 12.0p dearer at the median (209.9p against 197.9p). At other forecourts off the motorway, premium diesel is 20.0p dearer at the median (219.9p against 199.9p).

Each figure covers every forecourt reporting that grade to the Government’s Fuel Finder scheme, with out-of-date and implausible prices left out. The supermarket comparison breaks the grades down by kind of forecourt, the motorway services page covers prices on the motorway network, and the town pages show what each grade costs near you.

How much better would economy need to be?

Premium only pays for itself if it takes the car far enough further on each litre to cover the extra it costs. Because cost per mile is the price divided by the miles each litre gives, the economy gain needed is simply the price gap as a share of the standard price.

To pay for itself on fuel cost alone, super unleaded would have to take the same car 10.3% further on every litre than regular E10 unleaded. To pay for itself on fuel cost alone, premium diesel would have to take the same car 10.0% further on every litre than standard diesel.

For comparison, when the American motoring organisation AAA tested cars whose makers recommend premium petrol, economy improved by an average of 2.7%, and AAA concluded that the modest gains “do not offset the higher cost of premium gasoline”. Today’s break-even for super unleaded is well above that 2.7%. In cars built for regular fuel, AAA’s earlier tests found “no benefit” at all.

Does super unleaded help an ordinary petrol car?

Rarely. Standard unleaded in the UK is 95 octane and super unleaded is 97 octane or more, according to the government’s E10 guidance. The RAC says that “for many cars a premium fuel makes no discernible difference to their performance”, and Which? puts it the same way: “there’s usually little benefit” unless you drive “a high-performance or imported car that specifically requires a higher octane rating than standard unleaded”. When Consumer Reports tested two SUVs whose makers recommend premium, both returned the same fuel economy on regular and on premium.

The fuel that matters is the one your handbook specifies, which is what AAA urges drivers to follow. The RAC’s rule of thumb is that a higher octane than recommended is safe but may bring no advantage, while a lower one than recommended could damage the engine. Some high-performance cars need super unleaded, and for those it isn’t optional.

What about E10 and older cars?

Super unleaded is also the UK’s E5 grade, with no more than 5% ethanol against up to 10% in regular petrol. The government says all new cars made since 2011 can use E10, and most cars and motorcycles made since the late 1990s are approved for it; anything that isn’t can use super unleaded instead. Its E10 vehicle checker answers the question for a specific car, and our fuel types explained covers the grades in more detail.

The extra ethanol does cost a little economy: the government puts it at around 1%, “unlikely to be noticeable in everyday driving”. Today's break-even for super unleaded is well above that, so the lower ethanol content alone doesn't pay for the premium.

Is premium diesel worth it?

Usually not. Premium diesel, the RAC says, “usually has a higher cetane number – good for winter cold starts, and typically more and higher concentrations of detergent and other additives”. Whether those additives make a difference is another matter: Germany’s motoring club ADAC says it is extremely hard to verify whether they actually have a positive effect, and that standard fuels are suitable for normal use. To pay for itself on fuel cost alone, premium diesel would have to take the same car 10.0% further on every litre than standard diesel.

Sources

• E10 petrol explained, GOV.UK
• Check if your vehicle can run on E10 petrol, GOV.UK
• What is the best fuel for my car?, RAC
• How to save fuel and other money-saving driving tips, Which?
• Premium fuel in cars designed for regular (2016), AAA
• Premium fuel in cars that recommend it (2017), AAA
• Why you might not need premium gas, Consumer Reports
• Premiumkraftstoffe, ADAC

The prices, gaps and break-even figures are our own, from today’s national figures. How prices have moved over time is on the price history page, and the monthly price report sums up each month.

Prices on this page were read 13 October 2026 at 05:14. They refresh on their own; the analysis around them is dated at the top.