Should I use premium or plus gas?
In most cases, you should use the octane rating your car’s manufacturer recommends. Premium fuel is only necessary for engines with high compression or turbocharging, and mid-grade or “Plus” fuel is typically a compromise that may not provide a noticeable benefit in engines designed for regular.
This article explains what octane ratings mean, when premium or mid-grade might be worth it, how to decide at the pump, and the practical costs involved. It emphasizes following the owner’s manual and considering your driving conditions to make the most economical choice.
Understanding octane ratings
Octane rating describes a fuel’s resistance to pre-ignition or knocking under compression. It does not indicate how much energy the fuel contains or how clean it burns. Engines with high compression or certain turbocharged designs require higher-octane fuels to prevent knocking, while most everyday engines run fine on regular 87 octane.
What octane numbers mean
Common octane options include 87 (Regular), 89 (Mid-grade, often labeled Plus), and 91–93 (Premium). Higher numbers resist knocking better, but they do not automatically deliver more power or better mpg in engines designed for regular fuel. Brand labeling can vary, so check your regional naming (for example, Plus may correspond to 89 octane in many markets).
Here are the general guidelines drivers typically follow.
- Regular (87 octane) suits most modern cars designed for regular fuel and is usually the cheapest option.
- Mid-grade or “Plus” (often 89 octane) may be recommended for certain engines or operating conditions; if your manual lists 89 or you hear occasional pinging on regular, you might try 89 to see if it helps.
- Premium (91–93 octane) is required or strongly recommended for many high-performance, high-compression, or turbocharged engines. Using regular when premium is required can cause knocking and potential damage; if the manual says Premium Fuel Required, use premium.
- In many markets, higher-octane fuels offer no additional benefit for engines designed for regular; the extra cost may not be worth it unless your engine requires it.
Bottom line: match the octane to your engine’s needs and avoid paying extra for higher octane when it isn’t required.
When premium or plus is worth it
There are scenarios where higher octane can matter, but they’re not universal. Understanding your engine and driving conditions helps determine whether Premium or Plus is worthwhile.
Engines that truly require premium
Turbocharged engines, high-compression engines, or vehicles with performance tuning often specify Premium Fuel Required or Premium Fuel Recommended. In these cases, using regular can reduce performance or trigger knocking sensors, potentially affecting power delivery and long-term durability.
Could mid-grade help under certain conditions
On some engines, 89 octane (Plus) may reduce knocking or improve drivability in hot conditions, with towing, or when the engine is under heavier load. If the owner’s manual allows 89 or you notice knocking on regular, testing Plus for a few tanks could be worthwhile. Benefits, however, vary by vehicle, and cost considerations remain important.
Practical considerations at the pump
Beyond what your engine needs, cost and fuel composition matter. Ethanol content and detergent additives can influence performance and mileage slightly, but these factors don’t change the fundamental octane requirement for your engine.
Follow these practical steps to pick the right octane when you fill up:
- Check your owner's manual or the fuel-filler door sticker for the recommended octane category (Regular, Plus, Premium).
- If your vehicle tolerates regular and you don’t hear knocking, Regular is typically the most economical choice.
- If you hear knocking or notice reduced performance on Regular, try the next higher octane (Plus or Premium) for a few tanks to evaluate any benefits.
- Remember that higher octane doesn’t always improve mpg or power on engines designed for lower octane; weigh the cost against any observed benefits.
In practice, most drivers will not experience a meaningful, long-term performance increase from using mid-grade or premium fuels unless their engine requires it. Sticking to the recommended octane is usually the most sensible financial choice.
Summary
For the average driver, the best rule is to follow the octane rating specified by the vehicle’s manufacturer. Premium fuels are essential for engines with high compression or turbochargers, while mid-grade Plus can be appropriate only if the manual allows it or if regular causes knocking. Always consult the owner’s manual or the fuel door label, consider your driving conditions, and reserve higher octane fuels for when they are actually required to avoid unnecessary costs.
