The minimum size for a toilet room is 15 square feet. This is the smallest amount of overall space needed to accommodate the required distances between the floor and ceiling, toilet and sink. A toilet room is also known as a half-bath or powder room.
The International Residential Code, or IRC, requires that a certain amount of clear space be left between fixtures to allow for safe and comfortable use. The doorway must be at least 34 inches wide, which is large enough to accommodate a door that is 2-foot and 10-inches tall at minimum. The code requires 15 inches of side-to-side clearance from the centerline of the toilet to the wall, which means that the width of the room must be a minimum of 30 inches at its narrowest point.
There needs to be at least 30 inches of clear space between the front edge of any fixture, such as a toilet, sink or bidet and the wall. This includes a minimum of 21 inches of standing space in front of the sink. For these requirements to be met, the room must be a minimum of 52 inches long. The ceiling needs to be a minimum of 80 inches above the toilet.
Compact toilets and small-scale sinks can be used to make a small toilet room feel more spacious. Large mirrors can also be added to create the illusion of a larger room. Check local building codes before embarking on a toilet room or any other household building project.