How to Figure Roof Height

Climb a ladder to access your roof.

Stand at the highest point of the roof and extend a tape measure downward until it reaches the ground. This measurement indicates the upper range of the roof's height. If the tape measure isn't long enough, extend a rope or string from the top of the roof to the ground. Mark the string at the roof's highest point and measure the string to find the height of the roof.

Stand near the edge of the roof and measure downward to the ground, using a tape measure or string. This is the lower range of the roof's height.

Measure 12 inches on a level and mark the 12-inch point on the level itself.

Hold the edge of the level against the roof at a point that is at least 12 inches from the roof's edge. Extend the level out horizontally so it is completely straight.

Measure downward from the 12-inch mark on the level to the roof itself and record this measurement.

Express your measurement in fraction form to indicate the roof's pitch. Place the number 12 in the denominator and the distance from the level to the roof in the numerator. For example, if you measured 10 inches from the level to the roof, your roof's pitch would be 10/12. This measurement can also be written with a dash or ratio sign as follows: 10-12 or 10:12.