RON 97+ vs RON 99: which petrol should you use?
Compare premium petrol labels, price and whether the stop is worth the extra drive before choosing a super unleaded stop.
Higher RON can matter when the engine is built or tuned for it.
RON is an octane rating. Higher RON petrol resists knock better, which matters for some high-performance, high compression or tuned engines. If your owner's manual or tuner specifies 98 or RON 99, do not treat a cheaper lower-RON product as the same thing.
Route & Fuel helps separate RON 97+ and RON 99 searches from wider Super unleaded E5 prices. Availability varies by site.
Check the car first, then compare the price.
For fuel choice, your owner’s manual and fuel flap label matter more than a one-size-fits-all website recommendation. If your car asks for a minimum RON, use that or higher.
| Fuel / label | What it usually means in the UK | Who should care |
|---|---|---|
| E10 petrol | Standard 95 RON petrol with up to 10% renewable ethanol. | Most modern petrol cars, unless the vehicle is not E10 compatible. |
| Super unleaded E5 | Higher octane petrol, generally RON 97+ or higher, with up to 5% ethanol. | Older E10-incompatible cars, some performance cars, tuned cars and drivers whose owner's manual asks for higher octane. |
| RON 97+ / RON 99 | RON is the octane rating. Higher RON resists knock better in engines designed or tuned to use it. | Cars that require or recommend high-octane fuel; benefits in ordinary engines are usually limited. |
Do not chase the wrong premium pump.
For premium petrol, the cheapest E5 price is only useful when the octane, detour, how far each stop is from your journey and fill size all make sense. The app helps compare those factors before you choose a stop.