If you need to figure the area of your ceiling for determining the size of a heater or air conditioner for a room, the process is simple. Some companies that sell ceiling fans will require you to find the pitch of your ceiling to figure if you need a special attachment for mounting the fan on a sloped surface. If you have different layers in your ceiling, the exact pitch will be different and the process is a little more complicated. However, for rooms with a straight-sloped ceiling, the calculations are easy.
Measure the height from the top part of the ceiling, straight to the floor. This might entail standing on a ladder or using a pole. Keep the measuring utensil straight up and down. Write this measurement down.
Measure the height of your walls in the same room, from the floor to where they join the ceiling. Subtract this measurement from the ceiling height measurement to get the rise of your ceiling.
Measure from the same point where you measured up to the ceiling, but this time, horizontally across the floor to the wall to get the run of your ceiling. Write this measurement down.
Sacle the measurements from feet to inches. For instance, if the rise of your ceiling is 12 feet 6 inches, record 12 1/2 inches to scale back your draft. If the run of your ceiling is 10 feet, mark this down as 10 inches.
Create a triangle with your measurements using a straightedge and a protractor on a piece of paper. Use the straightedge to draw a horizontal line the length of your converted run measurement. At the left side of the line, draw a line straight up (90 degrees on the protractor) the length of the converted ceiling rise measurement. Connect the two ends of the lines.
Calculate the angle formed between the bottom line and the sloped line on the right, using the protractor. Place the center point of the protractor on the endpoint on the right side of the bottom line and see where the sloped line lines up on the protractor. This is the angle of your ceiling's pitch.