Petrol vs Diesel vs E10 — What's Actually in Your Tank?

A guide to the fuels on UK forecourts

Modern UK fuel isn't as simple as "petrol or diesel" — most pumps now offer several variants, and using the wrong one matters more than many drivers realise.

E10 and E5 — what's the difference?

E10 is the UK's standard unleaded petrol, containing up to 10% renewable ethanol. E5 (often labelled "Super Unleaded" or "premium") contains up to 5% ethanol and is required by some older vehicles not designed for E10.

Standard vs premium diesel

Standard diesel (B7) contains up to 7% biodiesel and is the default at most pumps. Premium diesel (B7P) is a higher-additive formulation some manufacturers recommend for better engine performance, usually at a higher price.

Why it matters which one you choose

Using the wrong fuel type for your vehicle can affect performance or, in rarer older-vehicle cases, cause damage — always check your vehicle handbook if you're unsure which fuel type it needs, rather than assuming standard is always safe.

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