can you mix 95 and 91 petrol

Yes—you can mix 95 and 91 petrol, and your car won’t immediately throw a tantrum.

The resulting octane is roughly the weighted average, so it’ll behave like something between 91 and 95 RON.

If your car requires 95 RON or higher, keep it on 95+; a splash of 91 in a pinch is usually fine, but living on the lower mix can mean reduced performance and potential knock.

If it merely recommends 95, mixing won’t hurt—your ECU will adapt and you might just lose a smidge of pep.

High-compression or turbo engines are fussier, so read the fuel flap and the manual like it’s gospel.

Bottom line: mix if you must, but aim for the grade your manufacturer specifies.