In cases where a roof has a complex shape such as in the image to the right measuring the dimensions and areas of each part of the roof to calculate total area will result in a more accurate measurement of area.
Figure squares for roof.
Convert the area to roofing squares.
If your roof is flat or has no more than a 3 in 12 pitch you can calculate its total square footage by simply multiplying the length by the width.
The answer is the number of roofing squares for the roof.
Shingles and other roofing materials such as underlayment are typically measured in squares that are 10 feet long and 10 feet wide with each square measuring 100 square feet.
Steep roofs measure your house at ground level then add in the roof s overhang for greater accuracy.
To calculate the size of the roof you need to measure the size of the roof as if it were flat account for roof pitch calculate square footage and finally determine how many squares of material are required for the roof the calculator above can handle all of this simply enter the length width and pitch and it will determine the size of the roof in squares.
The calculator cannot account for complex shapes based on a measurement of square footage alone.
Get the square footage of roof and divide it by 100 and it will give the number of squares you need and for every decimal number over 3 buy a bundle to achieve the amount of material.