Premium gas contains a higher concentration of octane, which helps to improve engine performance. As a result, premium gas can lead to slightly better gas mileage. However, the difference is usually only a few cents per gallon, and it may not be worth the extra cost for most drivers. Ultimately, the best way to improve gas mileage is to keep your car in good condition and practice fuel-efficient driving habits. So while premium gas might give you a slight edge in terms of mileage, it's not the magic solution to high fuel costs.