Fuel Types Explained — Petrol, Diesel, E10

Fuel types explained — the quick answer

The label matters more than the name: ‘E10’ petrol holds up to 10% ethanol, ‘B7’ diesel up to 7% biodiesel, and every EU pump is now marked this way. Put petrol in a diesel car (or vice versa) and it means expensive damage — stop, and don’t start the engine, if you do. Which grade your car needs, and how to read foreign pumps, is below.

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This guide explains every fuel type you are likely to encounter at a petrol station in Europe and beyond. From standard petrol and diesel to E10, LPG, and AdBlue, we cover what each fuel is, who should use it, and how to identify the correct pump when driving abroad. Whether you are planning a European road trip or simply want to understand what goes into your tank, this is your complete fuel reference.

Petrol Grades and Octane Ratings

Petrol or gasoline is available in different grades defined by their octane rating, measured as RON (Research Octane Number) in Europe and AKI (Anti-Knock Index) in North America. The octane rating indicates the fuel resistance to premature detonation or knocking in the engine.

In Europe, the standard petrol grade is 95 RON, sold as Euro 95, Super, or Sans Plomb 95 depending on the country. Premium petrol at 98 to 100 RON is also widely available and sold as Super Plus, Ultimate, V-Power or similar brand names. Higher octane petrol allows more advanced ignition timing and higher compression ratios, which is why performance and turbocharged engines often require 98 RON.

Using a lower octane than specified by your vehicle manufacturer can cause engine knock, reduced power, and potential engine damage. Using a higher octane than required is safe but offers no benefit in engines designed for standard fuel.

Understanding E5 and E10

Ethanol blending is now standard practice in fuel production to reduce carbon emissions. E5 petrol contains up to 5 percent bioethanol blended with fossil petrol, while E10 contains up to 10 percent. The E stands for ethanol and the number indicates the maximum percentage.

E10 became the standard petrol grade in France in 2009, in Germany in 2011, and in the United Kingdom in 2021. The EU Commission mandated standardised fuel labelling in 2018, showing E5 in a circle on pumps and fuel filler caps for easy identification.

The transition to E10 has caused concern among owners of older vehicles. Ethanol can degrade certain rubber seals, fuel hoses, and carburettor components in vehicles not designed for it. Cars built after 2011 are almost universally compatible. For vehicles between 2000 and 2011, compatibility varies by manufacturer. Cars built before 2000 and classic vehicles should generally use E5 which remains available as a premium option at most stations.

From a driving perspective, E10 has slightly lower energy content than E5, resulting in approximately 1 to 2 percent lower fuel economy. This difference is negligible for most drivers but means you may fill up very slightly more often.

Diesel Fuel Types

Diesel fuel in Europe is classified by its biodiesel content. B7 diesel contains up to 7 percent biodiesel and is the current standard grade across most of Europe. B10 contains up to 10 percent and is becoming available in some countries. XTL is a synthetic diesel produced from non-petroleum sources.

The EU fuel label for diesel is a square shape, distinguishing it from the circular petrol label. B7, B10 and XTL are shown inside the square at the pump. This labelling system is consistent across all EU member states, making it easier for drivers travelling between countries.

Standard diesel is suitable for all modern diesel engines. Premium diesel grades offered by fuel companies such as Shell V-Power Diesel, BP Ultimate Diesel, or Total Excellium claim to offer better engine cleaning, improved performance, and reduced emissions through proprietary additive packages.

AdBlue for Diesel Vehicles

Most diesel vehicles manufactured after 2015 use Selective Catalytic Reduction (SCR) technology to reduce nitrogen oxide emissions. These vehicles require AdBlue, a urea-based solution stored in a separate tank. AdBlue consumption varies but is typically 1 to 3 litres per 1,000 km.

Running out of AdBlue triggers an engine management warning and eventually restricts engine power or prevents the engine from restarting. AdBlue is available at most fuel stations, often at a dedicated pump alongside the diesel pump, and can also be purchased in containers from auto parts shops and supermarkets.

EU Fuel Labelling System

Since 2018, all EU member states plus Iceland, Liechtenstein, Norway, Switzerland, Turkey, Serbia and North Macedonia use a standardised fuel labelling system. The labels appear on fuel pumps, in fuel filler caps, and in vehicle manuals.

This system makes it much easier for drivers travelling across borders to identify the correct fuel. Before driving abroad, check which fuel your vehicle requires and familiarise yourself with the EU label. Our road trip Europe checklist includes fuel preparation as part of cross-border driving planning.

LPG and Autogas

Liquefied Petroleum Gas is used as vehicle fuel in many countries and offers cost savings of 40 to 60 percent compared to petrol. The Netherlands, Poland, Italy and Turkey have particularly extensive LPG station networks. Some vehicles are factory-equipped for LPG while others can be retrofitted with conversion kits.

The main challenge for LPG drivers travelling across borders is that pump connector types differ between countries. Four main connector types exist in Europe: the ACME thread (common in Germany and Belgium), the Bayonet fitting (common in the Netherlands and UK), the Dish coupling (common in France, Spain and southern Europe), and the Euronozzle. Carrying a set of adapters is essential for cross-border LPG driving.

Fuel Prices Across Europe

Fuel prices vary significantly between European countries due to different tax levels. As a general guide, fuel is most expensive in Scandinavia, the Netherlands and the United Kingdom and cheapest in Eastern Europe, particularly Poland, Romania and Bulgaria.

The price difference can be substantial. A litre of petrol may cost EUR 1.50 in Luxembourg but EUR 2.10 in the Netherlands, a difference of 40 percent. Savvy travellers plan their fill-ups accordingly, topping up in cheaper countries before crossing into more expensive ones.

For Germany, fuel prices fluctuate significantly during the day, typically being cheapest in the early evening between 18:00 and 20:00. Navigation apps with fuel price comparison features can help you find the cheapest stations along your route.

Misfuelling Prevention and Recovery

Putting the wrong fuel in your vehicle is a costly mistake that affects approximately 150,000 drivers per year in the UK alone. Putting petrol in a diesel vehicle is the most common error and potentially the most damaging. Petrol strips the lubrication from diesel fuel injection components, potentially causing thousands of euros in damage.

Modern diesel filler necks are narrower than petrol ones, making it physically difficult to insert a petrol pump nozzle. However, it is still possible with force. Diesel pump nozzles are too large to fit into most petrol filler necks, making the reverse error rare.

If you realise you have added the wrong fuel, do not start the engine. Call your roadside assistance provider and have the tank drained and flushed professionally. If you have started the engine, stop immediately and call for assistance. The further you drive, the more damage occurs.

Electric Charging as an Alternative

While this guide focuses on liquid fuels, the rapid growth of electric vehicles means that charging infrastructure is increasingly relevant for drivers. See our dedicated guide on electric vehicle road trips for comprehensive information on charging networks, range planning, and EV-specific considerations for travelling across Europe and beyond.

Tips for Fuelling Abroad

Before driving abroad, know your vehicle fuel type and any restrictions on ethanol content. Download a fuel station finder app that covers your destination countries. Carry a credit card as many unattended fuel stations in Europe only accept cards. Check whether your card requires a PIN for pump-pay transactions.

At the pump, look for the EU fuel label on both the pump and your vehicle fuel filler cap. If in doubt, ask station staff. Never use a fuel type you are unsure about as the repair costs far exceed any inconvenience of asking for help. For more advice on driving abroad, see our car rental tips and international driving permit guide.

Conclusion

Understanding fuel types is essential for every driver especially when travelling internationally. Know your vehicle fuel requirements, familiarise yourself with EU fuel labels, be aware of the differences between E5 and E10 petrol, and always double-check before filling up in an unfamiliar country. The few seconds spent confirming you have the right pump can save you thousands in repair bills. With the right preparation, fuelling up abroad is just another straightforward part of the driving experience.