In real estate terminology, an apartment that has three bedrooms, a living room or hall (H) and a kitchen is a 3BHK flat interior design. Of the three bedroom designs, the largest would be the master bedroom which comes with an attached bathroom. The other two bedrooms can belong to kids or the parents of the homeowners and the third one can be a guest room or double up as a study, library, den or home office. A 3BHK house plan comes with two toilets.