You will need
  • Measuring tape
Calculate area of walls in one room is very simple.
The total area needs to be folded from square of all the (usually) four wallsOK, they're all the same, but some have Windows, doors and similar structures. S=S1+S2+S3+S4.
To find the area of one of the walls, you should multiply the height of the walls of theing on its length. If it does not, it will be the first area S1. Similarly, the calculated area of the other three walls S2, S3, S4. And the area of those walls, where there is, for example, window, calculated as: measured width and length of the window are multiplied by each other, it turns out the square window, the size of a wall, s is subtracted the area of the window, this will be the area of the wallss, where encased window, door, etc.