Access one of the rafters then take. How to calculate roof pitch. First use your measuring tape to measure 12 inches on your large level and make a mark at the 12-inch line.
Given pitch and a horizontal area measurement multiply the horizontal area by a correction factor corresponding to pitch provided in the table below to determine the actual area of the roof to be used in the Roofing Material Calculator.
In the attic place the level against a rafter with the. The pitch is commonly defined as the ratio of rise over run in the form of x12. Measure 12 inches on a carpenters level. Rafter² rise² run² from the Pythagorean theorem.