Fuel types in Australia, explained

Unleaded 91 (U91)

The most common fuel in Australia. U91 has a research octane number (RON) of 91 and works in the vast majority of modern petrol vehicles. It's the baseline price on the board and the cheapest petrol option at most stations. Unless your owner's manual specifies otherwise, U91 is what your car is designed to run on.

Ethanol 10 (E10)

E10 is regular unleaded with up to 10% ethanol blended in. It's typically a few cents cheaper per litre than U91, but it contains slightly less energy per litre, so you'll usually burn around 2–3% more fuel to cover the same distance. That usually cancels out the saving.

Not all engines are E10-compatible — check your owner's manual or the Australian Government's E10 compatibility list before using it. Most petrol cars made after 2005 can run E10 safely, but older cars and some small engines cannot.

Unleaded 95 and Unleaded 98 (U95 / U98)

Premium unleaded fuels with higher octane ratings. Cars with high-compression engines or turbochargers — typically European sedans, performance cars, and many late-model SUVs — are designed to run on U95 or U98. Using a lower-octane fuel in these engines can cause knocking and, over time, real damage.

For everyday sedans designed for U91, premium fuels don't deliver better performance, better economy, or a cleaner engine, despite marketing claims. The extra 15–30 cents per litre is money you're handing to the retailer for nothing. Check your fuel door — if it says “Unleaded Petrol” with no octane requirement, U91 is fine.

Diesel

A separate fuel entirely — never put diesel in a petrol engine or petrol in a diesel engine. Diesel is typically priced similarly to U95 and is the standard for most utes, 4WDs, trucks, and many European SUVs. Diesel engines deliver more torque and better highway fuel economy than equivalent petrol engines, which is why they dominate long-haul and towing applications.

LPG (Autogas)

Liquefied petroleum gas, typically priced at roughly half of petrol per litre. Fewer than 10% of Australian stations still sell LPG, and availability continues to shrink as factory LPG vehicles have stopped being produced. If you run LPG, Refuelr's LPG filter shows every station in the country that still offers it.

So which one should you use?

Check your vehicle's fuel door or owner's manual. If it says “Unleaded Petrol Only” with no octane specified, U91 or E10 (if your car is E10-compatible) are your cheapest options and perform identically. If it says “95 RON minimum” or “98 RON minimum,” don't go below that — the short-term saving is not worth the long-term engine wear.

Refuelr's fuel-type filter lets you compare prices for whichever fuel your car needs. Set it once and the map and list will always show the right numbers.