Many exchange students and foreigners who look for accommodations before they come to KOREA end up becoming disappointed.
This usually happenes, when they arrive at their accommodation and then they see their room.
They may feel confused and disappointed. Because the room size is so different with their previous room information.
So, you have to ask the accommodation's owner the "ACTUAL ROOM SIZE" not including the common facilities.
In most cases, Koreans include common facilities such as hallway, stairs, elevator, common bathrooms and toilets to their "ROOM SIZE"
So, unless you are looking at the actual room, you have to ask the owner for "THE ACTUAL ROOM SIZE"