Is premium 98 better for my car?

Only if your car requires or recommends it. For a car designed to run on 91, using 95 or 98 usually gives no meaningful benefit and costs more. Cars that specify premium should use it.

Can I use E10 in my car?

Most petrol cars built in the last two decades are E10 compatible, but not all. Check your owner's manual, the inside of the fuel flap, or your state's E10 compatibility checker before using it.

Does E10 give worse fuel economy?

Slightly. E10 has a little less energy than standard unleaded, so economy can drop by roughly 3 percent. It is usually cheaper per litre, so the total cost can still work out lower.

E10 vs 91 vs 95 vs 98: Which Petrol Should You Use?

The short version:

The number is the octane rating (RON) — how well the fuel resists knocking, not how "powerful" it is.
Use the minimum octane your manufacturer specifies. Higher octane than required is usually wasted money.
E10 is normally cheapest but slightly less efficient — and only for E10-compatible cars.

Standing at the bowser choosing between four buttons is one of the most common — and most misunderstood — decisions drivers make. Here's what actually matters.

What the numbers mean

91, 95 and 98 are octane ratings (RON — Research Octane Number). Octane measures how resistant a fuel is to pre-ignition, or "knocking". A higher number doesn't mean more power or cleaner fuel by itself — it means the fuel can handle higher compression before it ignites early. E10 is a blend of regular unleaded with up to 10% ethanol, and sits at roughly 94 octane.

Fuel	Octane (RON)	Notes
E10	~94	Up to 10% ethanol. Usually cheapest. Slightly less efficient. E10-compatible cars only.
Unleaded 91	91	The standard fuel most cars are designed for.
Premium 95	95	For cars that require or recommend premium.
Premium 98	98	Highest octane; often has extra cleaning additives.

The one rule that matters

Use the minimum octane your car's manufacturer specifies — you'll find it in the owner's manual and often printed inside the fuel flap. Two things follow from this:

If your car is built for 91, filling up with 95 or 98 generally gives no meaningful gain in power or economy. You're paying a premium for octane the engine can't use.
If your car requires premium (common in many turbocharged, performance and European models), you should use it. Running lower octane than specified can cause knocking, and the engine will pull timing to protect itself — hurting performance and economy.

Is E10 worth it?

E10 is usually the cheapest option on the board. The catch is a small efficiency penalty — around 3% fewer kilometres per litre because ethanol carries a little less energy. In most cases the lower price more than offsets that, so E10 still comes out cheaper per kilometre. Just confirm your car is E10-compatible first: check the manual, the fuel flap, or your state's online E10 checker.

Compare prices for your exact fuel

Bowserly lets you filter by E10, 91, 95, 98, diesel or LPG and shows the cheapest nearby station for that fuel.

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Frequently asked questions

Will premium clean my engine?

Premium fuels often contain extra detergents, but for a car designed for regular, that's rarely worth the price difference. Modern regular fuels already meet strict standards.

Can I mix E10 and 91?

Yes — if your car is E10 compatible, mixing is fine. There's no harm in alternating between them.

Does higher octane give more power?

Only in engines designed to take advantage of it. In a standard engine tuned for 91, higher octane won't add power.