What is the Difference Between a Coupe and a Sedan?

Many definitions of a coupe and a sedan will define the coupe as a two-door or three-door model that is roughly equivalent to the sedan. A sedan almost always has four doors in contrast. Actually there are four-door coupes, and two-door sedans, so the differences between a coupe and a sedan automobile may not always be quite clear.

In reality, a coupe is strictly defined by its interior volume or space. Distinctions between a coupe and a sedan has little to do with doors and are made clear by the Society of Automotive Engineers (SAE), which standardizes definitions of the different types of cars on the market. Measurements of a coupe and a sedan are as follows:

• Coupe equals less than 33 cubic feet (.934 cubic m).
• Sedan is equal to or greater than 33 cubic feet.

Thus a coupe and sedan can be determined by volume alone rather than being determined by number of doors. A two-door car with a larger than 33 cubic foot volume or interior space is essentially a two-door sedan. Likewise, a four-door car with less than a 33 cubic foot volume is a four-door coupe.

Nevertheless, many manufacturers call a car a coupe when they want to evoke a sportier concept for the car. They may include the name coupe in the car, though technically what you are really buying is a sedan. The Cadillac Coupe de Ville is a classic example of what is really a two-door sedan. So it can get difficult to determine the differences between a coupe and a sedan when the word coupe is added to the name of the car.