A studio apartment, also known as a studio flat (UK), efficiency apartment or bachelor apartment, is a small apartment which combines living room, bedroom, and kitchenette into a single room. "Bachelor" or "efficiency" apartments are sometimes smaller than studio apartments
 
Studio, efficiency, and bachelor style apartments all tend to be the smallest apartments with the lowest rents in a given area, usually ranging around 300 to 450 square feet (25–45 square metres) in the United States, but considerably smaller in countries such as Japan, South Korea, and several European capitals.
 
A variation common in New York City is the "L-shaped" or "alcove" studio, in which the central room branches off into a small alcove that can be used for sleeping or dining.