Formula C was also an open wheeled SCCA racing class originating in the mid 60s, derived from the failed Formula Junior class. Formula C cars were very similar to Formula Juniors; Formula B was a similar class with uprated 1600 cc engines. Formula C cars were limited to 1100 cc engines. In the SCCA today, Formula Continental is the direct descendant of Formula C.

Open-wheel car, formula car, or often single-seater car in British English, describes cars with the wheels outside the car's main body and, in most cases, one seat. Open-wheel cars contrast with street cars, sports cars, stock cars, and touring cars, which have their wheels below the body or fenders. Open-wheel cars are usually built specifically for racing, frequently with a higher degree of technological sophistication than in other forms of motor sport.

A typical open-wheeler has a minimal cockpit sufficient only to enclose the driver's body, with the head exposed to the air. In modern cars the engine is often located directly behind the driver, and drives the rear wheels. Depending on the rules of the class, many types of open-wheelers have wings at the front and rear of the vehicle, as well as a very low and virtually flat undertray that helps achieve additional aerodynamic downforce pushing the car onto the road.

Some major races, such as the Singapore Grand Prix, Monaco Grand Prix (sanctioned by Formula One) and the Long Beach Grand Prix (sanctioned by Indycar), are held on temporary street circuits. However, most open-wheel races are on dedicated road courses, such as Watkins Glen International in the US, Nürburgring in Germany, and the Bahrain International Circuit in the Middle East. In the United States some top-level open-wheel events are held on ovals, of both short track and superspeedway variety, with an emphasis being placed more on speed and endurance than the maneuverability inherently required by road and street course events. The most well-attended oval race in the world is the annual Indianapolis 500 (Indy 500) in Speedway, Indiana, sanctioned by Indycar; in the United States, it is common to refer to open-wheel cars as Indy Cars because of their recognizable appearance at the Indy 500.