How to Measure a room
for a Square or rectangular room:
To measure the area and the perimeter of a standard square or rectangular room, you can always use the simple formulas below.
(Length) x (Width) = Area
(Length) + (Width) = Perimeter
FOR an odd shaped room:
Calculate the area of the individual recesses or protrusion by measuring their length and width first. Then measure the rest of the rectangular room. Lastly, add all of the areas together to get the total area of the room.
When calculating the area of U-shaped rooms, use the same method of adding the individual areas together, except when measuring the area of a round recess. To calculate the area of a round recess, measure the longest width and length of the recess, normally through the center of the space first. Next, divide the length in half and multiply that number by the width. Once you have this calculated, multiply the total by pi (3.14). This will give you the area of the complete circle. However, only half of the circle extends beyond your wall (pictured above), so divide the area in half. Now you have the area of the U-shaped protrusion in your room. You can add this number to the area of the other measurements in your room for the total area.
To calculate the area of a wall, use the standard formula of (Length) x (Width) = Area. Next, use the same formula to record the individual area of windows and doors. Once you have all of these measurements down, subtract the area of the windows and doors from the total area of the wall. This will help you calculate how much paint or wallpaper you need for a room without having lots of excess when you're finished.