Australian service stations sell regular unleaded (91), premium unleaded 95 and premium unleaded 98. Right now Premium 95 costs about 15.8¢ a litre more than Unleaded 91 in NSW, and Premium 98 about 23.8¢ more. On a 50-litre fill that adds up quickly, so it's worth knowing whether your car needs it.
What the numbers mean
91, 95 and 98 are octane ratings (RON): how well the fuel resists "knocking", where fuel ignites too early in the engine. Higher-octane fuel lets engines with high compression or turbochargers run as designed. It doesn't contain more energy.
Which cars need premium?
- If your car requires 95 or 98 (check the fuel flap or manual), use at least that. Using a lower grade can reduce performance and, over time, may cause engine damage.
- If it recommends premium, it will usually run on lower grades but may be a little less powerful or efficient.
- If it's designed for 91, premium generally gives no real benefit. Most everyday cars fall into this group.
Is 98 better than 95?
Only if your car calls for 98. If it needs 95, 98 usually won't make a noticeable difference.