FuelFacts

What gas does my car take? Premium vs regular, and what octane really means

The short version: use the octane your owner's manual lists — no more. Here's how to find your car's exact fuel, what the pump numbers mean under federal law, and when premium is actually worth paying for.

Not sure what your car takes? Look up your exact year, make and model → — FuelFacts shows the fuel the EPA recorded for every trim, from the public-domain 49,995-car federal dataset.

Three ways to find your car's fuel — fastest first

What the octane number (87, 89, 91, 93) actually means

Octane measures a fuel's resistance to "knock" — premature ignition that stresses an engine. The number on the yellow pump sticker isn't marketing; it's set by federal rule. The FTC's Fuel Rating Rule defines the octane rating as the anti-knock value found by "dividing by 2 the sum of the research octane number plus the motor octane number" — the (R+M)/2 figure, also called the Anti-Knock Index (AKI).

That same rule requires retailers to post the rating on a label "on each face of each dispenser," in full view near the price — which is why an octane label sits on every pump in the country. Typical grades: regular ≈ 87, midgrade ≈ 89, premium ≈ 91–93.

Source: FTC Fuel Rating Rule, 16 CFR Part 306 (§ 306.0 octane definition; § 306.10 dispenser posting).

"Required" vs "recommended" premium — the distinction that decides it

This is the one thing that matters, and it's in your manual, not the data. If premium is required, use it — these engines (often turbocharged or high-compression) are built for it. If it's only recommended, the federal fuel-economy site is blunt about the payoff: under normal driving "you may get little to no benefit," and "the cost increase is typically higher than the fuel savings."

Source: EPA/DOE FuelEconomy.gov, Selecting the Right Octane Fuel.

Does paying for premium actually help?

For a car designed for regular, no. The FTC's long-standing consumer guidance: "ordinarily, your car will not benefit from using a higher octane than is recommended in the owner's manual," and unless the manual "calls for high octane fuel or your engine is knocking, there's no reason to pay for premium." Higher octane doesn't add power or clean your engine on its own — it only resists knock.

Source: U.S. Federal Trade Commission consumer guidance on gasoline octane (consumer.ftc.gov).

How FuelFacts answers this for your exact car

The EPA records the fuel each manufacturer specified for the official mileage test, trim by trim — which is why one version of a model can read "premium" and another "regular." We show you that recorded grade for your exact car, dated to when we pulled it. What the EPA dataset does not record is required-vs-recommended — so for that last step we send you to your manual instead of guessing.

Cars that take premium → · Where fuel grade depends on the trim → · Is premium worth the money? →

FAQ

What kind of gas does my car take?

Check the fuel-filler door or gas cap, or your owner's manual — or look up your exact year, make and model on FuelFacts to see the fuel grade the EPA recorded for that trim. Most cars take regular (87 octane).

How do I know if my car needs premium gas?

Your owner's manual is the only place that says whether premium is required or just recommended. If it's required, use it; if it's only recommended, the EPA and DOE say most drivers get little to no benefit under normal driving.

What does the octane number 87, 89 or 91 mean?

It's the fuel's anti-knock rating, calculated as (R+M)/2 under the FTC Fuel Rating Rule (16 CFR Part 306). Regular is about 87, midgrade about 89, and premium about 91 to 93.

Will premium gas hurt a car that takes regular?

No, but it won't help either. The FTC says a car designed for regular gets no benefit from higher octane — you'd just pay more for no gain. Use premium only if your manual requires it or the engine is knocking.