Can my car use E10 petrol?

Almost all petrol cars built since 2011 are approved for E10, and many earlier models are too. Some pre-2011 cars, certain older mopeds and motorcycles, and most classic cars should stick to E5. Check the official GOV.UK E10 vehicle checker or your handbook if you are unsure.

Does E10 reduce fuel economy?

Slightly. Ethanol contains less energy per litre than petrol, so E10 typically reduces fuel economy by around 1% compared with E5 — small enough that most drivers will not notice it in day-to-day driving.

What happens if I put E10 in a car that isn't compatible?

A single accidental fill is generally not considered an emergency — you should not need to drain the tank — but repeated use in an incompatible vehicle can damage fuel system components such as seals, hoses and plastics over time. Switch back to E5 at your next fill.

Is E5 still available in the UK?

Yes. E5 remains on sale as super unleaded (97+ octane) at many forecourts, though not all stations stock it, and it costs more per litre than standard E10.

E5 vs E10 Petrol: What's the Difference?

In September 2021, the standard grade of petrol sold across Great Britain changed from E5 to E10 (Northern Ireland followed in 2022). If you drive a petrol car, the pump you almost certainly use today is labelled E10, while the more expensive "super unleaded" pump next to it is still E5. Here's what those labels mean, why the change happened, and what it means for your car and your fuel bill.

What do E5 and E10 actually mean?

The "E" number tells you the maximum percentage of renewable ethanol blended into the petrol. E10 contains up to 10% bioethanol; E5 contains up to 5%. The rest is conventional unleaded petrol, and both grades must meet the same British standard for petrol, BS EN 228. In the UK, E10 is sold as standard unleaded (95 octane), while E5 is now sold as super unleaded with a higher octane rating of 97 or above.

The switch to E10 was an emissions policy, not a performance one. Bioethanol is made from crops and plant material, so blending more of it into petrol reduces the net carbon dioxide emissions of every litre burned. The government estimated the change would cut transport CO2 emissions by a meaningful amount each year — roughly equivalent to taking hundreds of thousands of cars off the road.

Which cars can use E10?

The good news is that the vast majority of petrol vehicles on UK roads are fully compatible with E10. As a rule of thumb, virtually all petrol cars built from 2011 onwards are approved for it, and many models from well before then are too.

However, some vehicles should stick with E5. These include certain petrol cars from before 2011, some older mopeds and motorcycles (particularly those with small engines), and most classic and cherished vehicles. Ethanol attracts water and can degrade older rubber seals, hoses, gaskets and some metals and plastics used in historic fuel systems, so long-term use of E10 in an incompatible vehicle risks damage. If you're in any doubt, use the official E10 vehicle checker on GOV.UK or consult your handbook — don't guess.

If you do accidentally fill an incompatible car with E10 once, the general advice is not to panic: it's not like putting petrol in a diesel, and you shouldn't need the tank drained. Simply fill up with E5 next time and avoid repeating the mistake.

Does E10 affect fuel economy?

Slightly, yes. Ethanol contains less energy per litre than petrol, so a tank of E10 takes you marginally less far than the same tank of E5. The government's own estimate put the reduction in fuel economy at around 1% — small enough that day-to-day variation in traffic, weather and driving style will usually swamp it. It's worth knowing about, but for most drivers it is not a reason to pay the significantly higher per-litre price of E5.

What matters far more to your annual fuel bill is what you pay per litre in the first place. The gap between the cheapest and most expensive E10 in a single town is often larger than any economy difference between grades, so it pays to search for the cheapest stations near you or browse current fuel prices by area before you fill up.

When does E5 still make sense?

E5 super unleaded remains on sale for two groups of drivers. The first is owners of E10-incompatible vehicles — older cars, classics, and some motorcycles — for whom E5 is the safe choice. The second is drivers of high-performance cars whose manufacturers recommend or require 97+ octane fuel; for them, the octane rating is the point, and the lower ethanol content is incidental. We cover that decision in detail in our guide to whether premium fuel is worth it.

Bear in mind that not every forecourt stocks E5 any more — smaller sites in particular may only carry E10 and diesel. If your vehicle needs E5, it's sensible to check before a long journey. Our station directory shows which fuel types each site reports, and if you're travelling, the route planner can help you find suitable stops along the way.

The bottom line

For most drivers in most cars, E10 is the sensible default: it's the standard grade, it's the cheapest, and the roughly 1% economy penalty is trivial next to the price premium of E5. Use E5 if your vehicle isn't E10-compatible or if your manufacturer calls for high-octane fuel — and whichever grade you need, compare prices first, because the difference between forecourts is usually the biggest saving on offer.