The standard size of a square shower stall in the United States is 32 inches wide by 32 inches long. Larger showers are often 32 inches wide by 48 inches long, although homeowners with enough space can choose significantly larger showers.
Many people purchase shower kits that are standard sizes, but showers are relatively simple, and buyers can find shower walls in a wide range of sizes and choose custom width. Tile is popular for shower floors, and tile is easy to fit to any set of dimensions. A shower should have enough clearance for its components. Showers with swinging doors, for example, need to have enough space for the door to open.