Regular unleaded is a type of gasoline commonly used in vehicles. It typically has an octane rating of 87, which helps prevent engine knocking and allows for efficient combustion. This fuel is suitable for most cars and is often the least expensive option at the pump. Regular unleaded is different from premium gasoline, which has a higher octane rating, usually around 91 or 93. While some high-performance vehicles require premium fuel for optimal performance, most standard vehicles operate efficiently on regular unleaded. Using the appropriate fuel type can help maintain engine health and improve fuel economy.