Roof Area Calculators:
For each of the roof types pictured below, L = horizontal Length, W = horizontal Width, and H = vertical Height, all entered in feet. Slope in inches per foot may substituted for H.

Hip roofs can present a problem for height measurement, and the slope method may be substituted in place of height measurement. Since modern architecture has allowed the incidence of mixed slopes in a single structure, the calculator allows for entry of differing slopes for intersecting roofs.

For many roofs, dimensions can be taken from the ground or from a ladder. Be sure that your measurements include any overhang at the eaves. Height can often be measured at the end wall at the center of a gable.

Complex roofs may have numerous repeats of these shapes - perform a separate calculation for each section, then add the results together (on paper) to obtain total roof area. A "salt box" roof with unequal sides may be calculated as two separate shed roof shapes. An "A-Frame" roof is simply a gable with high slope.