Calculating the area of a room in square metres is simple in principle, although it can be a little tricky in a crowded or irregularly-shaped space.
Measure the length of one wall in metres. For example, the length of the wall is 8 m.
Measure the length in metres of the connecting wall on either side. For this example, the length of the connecting wall is 7 m.
Multiply the two lengths together. For this example, 8 multiplied by 7 equals 56. The area of the room is 56 square metres.
If the room is irregularly shaped, break it up into different areas and add them together. For instance, calculate the area of the main part of the room and any alcoves or entranceways separately, then total them to find the area.