What is octane?

Octane is a standard for measuring the quality of fuel. It's very similar to the RON rating used in the UK and Europe, but gives slightly different figures and is primarily used in North America. A higher octane rating means a fuel is less prone to 'knocking' – where the fuel ignites before you want it to – which means it'll usually perform better in high-performance engines. Almost all normal cars are able to run on the lowest octane rating fuel sold at petrol stations, but specialised sports cars might specify high-octane fuel.