A room is a subdivision of space within a building model, based on elements such as walls, floors, roofs, and ceilings. These elements are defined as room-bounding. Revit refers to these room-bounding elements when computing the perimeter, area, and volume of a room.
In Revit, you can turn on/off the Room Bounding parameter of many elements. You can also use room separation lines to further subdivide space where no room-bounding elements exist. When you add, move, or delete room-bounding elements, the room’s dimensions update automatically.
An area is a subdivision of space within a building model, typically on a larger scale than individual rooms. However, areas are not necessarily bounded by model elements. You can draw area boundaries or pick model elements to use as boundaries.