It’s often tempting to try to squeeze bathroom spaces when designing a house. A comfortably sized bathroom is worth the extra few inches though. The IRC says the minimum width from the centerline of the toilet to the nearest cabinet
When remodelling a house it& almost always possible to fit in a new half bath ó meaning a toilet and a sink. The real variable is the degree of convenience one can achieve when locating the new facilities in the space allowed.
half-bath tucked under a stairway. A half bath needn't be large. You will have enough space if you can find a spot in your house that's about 3 to 4 feet wide and 6 to 8 feet long. If it's any smaller, it will be uncomfortable for people to access