Regular, plus or premium: what should you fill up your car with?

There are three kinds of gas: regular, plus, and premium. Here’s a brief look at the different types and how you can determine which is best for your car.

Understanding the three fuel grades
The various types of gas have different octane ratings, which are a measurement of fuel stability. These ratings are based on the pressure at which a fuel will spontaneously combust in a test engine. The higher the number, the more stable the fuel. Regular gas has an octane rating of 87; plus gas has an octane rating that’s between 88 and 90, and premium gas has an octane rating that’s between 91 and 94.

Selecting the right type of gas for your car
The owner’s manual for your car will indicate what you should fill it up with. Always follow your car manufacturer’s recommendations.

If your car requires premium gas, this means that its engine has a high compression ratio and requires higher-octane fuel. Using regular fuel in a car that takes premium gas can affect engine performance, decrease fuel economy and even cause engine damage.

For cars that take regular fuel, however, there’s no need to fill up with a higher grade than advised. It costs more, and using it offers no benefits.

If your car manufacturer says that premium gas is recommended but not required, this means that the engine runs best on premium gas but can take a lower-grade fuel without the risk of engine damage.

If you aren’t sure which fuel grade to choose or can’t find this information in your owner’s manual, ask a qualified mechanic in your area.