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Would like to know why the big price difference between 91 and 95 octane petrol. It started at 5cents then went to 7, 9 cents difference. But now its 16cents different in price...Why?????

It may depend on the brand, or location. The standard price differential between 91 and 95 octane is 8 cents per litre, however 98 octane, which is sold by many BP and Mobil service stations instead, costs another 8cpl, or 16cpl more than 91. Gull also sell an ethanol-blended 98, but it's prices are slightly lower.

Also, there is some price discounting in parts of the country (e.g. Auckland, Whangarei, Rotorua), where some services stations are selling 91 under $2/litre. But 95 isn't being discounted, so at current prices would retail for about $2.17/litre.

For more information on the costs of different types of petrol, see the article in our latest Directions magazine.

I have say 6 petrol satations within about 10 to 15 mins walking distance and 95 octane is 16 cents more than 91 octane. so 91 is around the $2.02.