91 vs 95 vs 98 Petrol in NZ: Which One Does Your Car Need?
Pull up to the pump in New Zealand and you will usually see 91, 95 and sometimes 98. With fuel prices high, it is worth knowing which one your car really needs, and whether paying more for premium gets you anything at all.
This guide explains 91 vs 95 vs 98 petrol in plain English, what happens if you use the wrong one, and how to check what your car needs, including Japanese imports.
The Short Answer
Use the grade your car's manufacturer recommends. If your car is designed for 91, that is all it needs, and paying for 95 or 98 gives you no real benefit. If your car requires 95, you must use 95 or 98, as running it on 91 can cause engine damage over time.
Check the label inside your fuel flap or your owner's manual. If it says premium unleaded, use at least 95. If it just says unleaded, 91 is fine.
Which Grade for Which Car
| Grade | Suits | Rule of thumb |
|---|---|---|
| 91 (regular) | Most everyday petrol cars, including most Japanese imports built for regular fuel | Use 91 unless your car asks for more |
| 95 (premium) | Cars that require premium, many European cars, and many turbo or performance engines | Use at least 95 if the label says premium |
| 98 (premium) | High-performance engines that specify 98 | Only if the manufacturer recommends it |
Always check your owner's manual or the label inside the fuel flap for the minimum grade your car needs.
What Octane Actually Means
The number on the pump is the octane rating. It measures how well the fuel resists knock, which is when fuel ignites too early under compression. High-performance and turbocharged engines run higher compression, so they need higher octane fuel to run properly.
Higher octane does not mean more energy or more cleaning power. In an engine designed for 91, a higher grade simply burns the same way, so you pay more for no noticeable gain.
Using the Wrong Grade
Too Low
Using 91 in a car that needs 95 can cause knocking, extra heat and, over time, internal engine damage.
Too High
Using 95 or 98 in a car designed for 91 is safe but usually wastes money.
Modern Engines
Many engines can adjust to protect themselves on lower octane, but they lose power and efficiency.
Wrong Fuel Type
Petrol in a diesel, or diesel in a petrol car, is far more serious. Do not start the engine.
Mixing Grades
Mixing 91 and 95 is fine, as long as the result meets your car's minimum grade.
Check the Label
The fuel flap label or owner's manual tells you the minimum grade.
Japanese Imports and Fuel Grades
Many cars in New Zealand are Japanese imports, and Japan labels its fuel differently. Under the Japanese standard, regular petrol is rated above 89 octane and premium (often labelled high-octane) is rated above 96.
So a Japanese import designed for regular petrol runs happily on 91 here, while one designed for Japanese premium should use 95 or 98 in New Zealand. Most everyday Japanese imports, like the Aqua, Corolla and many SUVs, are designed for regular fuel, while many performance, turbocharged and European models need premium. The fuel flap label is the quickest way to check, and the Motor Trade Association notes the same model can need a higher grade in its imported version.
Is Premium Worth the Money?
Only if your car needs it. Premium costs more at the pump. On BP's published terminal gate prices for 27 October 2026, 95 was about 11 cents a litre more than 91 at the Wiri terminal, before retail margins, and the gap at the pump is often larger.
As a guide, a car using 7 L/100km over 15,000km a year burns about 1,050 litres. Every 10 cents a litre extra adds roughly $105 a year, so a 15 cent gap costs about $158. That is worth paying if your car needs premium, but a waste if it does not.
Our guide to the most fuel-efficient used cars shows how the car you choose affects your fuel bill far more than the grade you buy.
Check Your Car in Three Steps
Open the Fuel Flap
Look for the label that shows the minimum octane or says regular or premium.
Check the Manual
The specifications section lists the recommended grade.
Fill Up Right
Use that grade or higher, and avoid paying for more than you need.
Not Sure What Your Car Needs?
If you buy a car from 4Guys Autobarn and are unsure which fuel it takes, just ask and we will check for you. We are always happy to help with the practical side of owning your car, from fuel to servicing.
Our guide to how often you should service a used car is a good next read. Visit us at 20 Arthur Porter Drive in Hamilton, open seven days, or start online: browse our current stock and apply for finance. Not local? We offer delivery anywhere in New Zealand.
Frequently Asked Questions
- The number is the octane rating, which shows how well the fuel resists knock, an uncontrolled early ignition in the engine. Higher octane fuel can handle more compression before it ignites, which suits high-performance and turbocharged engines.
- Only if your car needs it. If your car is designed for 91, using 95 or 98 gives no noticeable benefit and simply costs more. If your car requires 95, you must use 95 or 98, not 91.
- It can cause knocking, also called pinging, and extra heat in the engine. Over time this can damage pistons, valves, rings and other internal parts. Modern engines can adjust to protect themselves, but they lose performance and efficiency.
- Check the label inside the fuel flap or the specifications section of your owner's manual. If the label says premium unleaded, use at least 95. If it just says unleaded, 91 is fine.
- In Japan, regular petrol is rated above 89 octane and premium above 96. A Japanese import designed for regular petrol runs on 91 in NZ, while one that needs Japanese premium should use 95 or 98 here.
- Only for cars that require it. For a car designed for 91, premium fuel is money wasted. At 7 L/100km over 15,000km a year, every 10 cents a litre extra adds about $105 to your annual fuel bill.
- Yes. Mixing grades simply gives you an octane rating somewhere between the two. Just make sure the result still meets your car's minimum requirement.
- If you put petrol in a diesel or diesel in a petrol car, do not start the engine, as this can cause serious damage. Call for help and have the tank drained. If you used a lower octane than recommended, fill up with the right grade as soon as possible and drive gently.
