E10 or E5 petrol: is super unleaded worth 17p a litre more?

Super unleaded now costs about 17.6p a litre more than standard petrol on average. FuelWise's figures for 24 October put the typical price of E5 at 191.1p a litre, against 173.5p for E10, so the choice between the two pumps matters more than ever. Here is what the difference is, who needs E5, and what the gap costs.

What E10 and E5 actually are

The number refers to the share of renewable ethanol blended into the petrol. According to the Department for Transport's guidance on GOV.UK, E10 contains up to 10% ethanol, while E5 contains no more than 5%.

Standard (95 octane) petrol became E10 in Great Britain in September 2021 and in Northern Ireland in November 2022. E5 is now sold as the "super" grade, at 97 octane or higher. Diesel did not change.

At the pump, both the dispenser and the nozzle carry a circular "E10" or "E5" label. The government says cars built from 2019 onwards should also have a label near the filler cap showing which fuels they can take.

Can my car use E10?

Most can. The government says around 95% of petrol vehicles on the road are compatible, and every new car made since 2011 is. Most cars and motorbikes from the late 1990s onwards are also approved by their makers.

The exceptions, according to GOV.UK, are mainly:

• classic, cherished and older vehicles
• some specific models, particularly from the early 2000s
• some mopeds, especially those of 50cc or under

The RAC puts the number of incompatible vehicles at as many as 600,000, and advises that drivers of cars registered before 2002 should not use E10.

The quickest way to find out is the government's E10 vehicle checker, which covers cars, vans, motorcycles and mopeds. You need the manufacturer, and possibly the model, engine size and year. If your vehicle is not listed, the guidance is to check the manual or ask the manufacturer, and to stick with E5 if in doubt. Garden machinery and boats may also need E5, so check before filling a can.

If you put E10 into a car that is not approved for it, the government says a single tank should not cause engine damage and you do not need to drain it; just use E5 next time. Prolonged use is what risks harm. Mixing the two grades in a compatible car is safe.

Is E5 worth paying extra for?

For a car that can run on E10, the numbers make it hard to justify on economy alone.

Ethanol carries less energy than petrol, so E10 gives slightly fewer miles per gallon. The government puts the reduction at around 1% and says it is unlikely to be noticeable. The RAC cites the US Energy Information Administration's estimate that economy may fall by about 3%.

Even taking the higher figure, E5 would need to cost only about 3% more than E10 to break even, roughly 5p a litre at today's prices. The actual average gap is about 17.6p, or around 10%.

In money terms, filling a 55-litre tank with E5 instead of E10 costs about £9.70 more at today's average prices. For someone filling up every fortnight, that adds up to roughly £250 a year. Some drivers of performance cars choose super unleaded for other reasons, but if your car runs happily on E10, the standard grade is the cheaper way to cover the miles.

Today's petrol prices at a glance

FuelWise tracks prices at 7,110 forecourts selling E10 and 5,069 selling E5. That gap reflects the government's note that some rural and small stations sell only one grade.

E5 has fallen 3.2p on average over the last 30 days. You can see the full picture on our E10 petrol prices and E5 petrol prices pages.

Where you buy matters as much as which grade you choose. Supermarket forecourts average 171.2p for E10, against 174.0p at other forecourts and 192.8p at motorway services. In other words, standard unleaded on the motorway now costs more on average than super unleaded across the UK as a whole.

By region, Northern Ireland is cheapest for E10 at an average of 165.7p, followed by the North East at 171.8p. See prices near you on the live map or the Northern Ireland page.

Why prices are where they are

Pump prices have been edging down, with 1,963 price cuts and 291 rises recorded in the last 24 hours, but the backdrop has worsened.

Oil has surged on the Iran war. Brent crude briefly passed $117 a barrel on Friday 23 October, its highest level during the war, after Iran's Revolutionary Guard claimed to have disabled seven tankers near the Strait of Hormuz, CBS News reported. The Associated Press, in the same coverage, said Brent had risen from less than $97 at the start of October. President Trump accused Iran on Thursday of lying about attacks on ships to push up oil prices before the US midterm elections, and the US ambassador to the UN, Mike Waltz, told the Financial Times the war could last another year.

Supply is recovering, but fragile. In its October Oil Market Report, published on 14 October, the International Energy Agency said Gulf crude exports had climbed to over 75% of pre-war levels in September, but warned that renewed attacks leave the recovery fragile. It also said record freight costs had squeezed refinery margins in Europe and that diesel markets remained under significant strain.

The pound has slipped slightly. Because oil is priced in dollars, a weaker pound makes fuel dearer here. Sterling was trading at about $1.337 on Friday, down around 0.16% on the day, according to FXStreet.

None of this changes the basic sums on E10 and E5, but it does mean every penny saved at the pump counts for more.

The short version

• Check your car on the government's E10 checker. If it is compatible, E10 is the cheaper choice.
• If your car needs E5, shop around: E5 prices range from 159.9p to 229.9p.
• Avoid motorway forecourts where you can; their E10 average is higher than the UK's average for super unleaded.