Roof Area Calculator

inches feet
1 .08
2 .17
3 .25
4 .33
5 .42
6 .50
7 .58
8 .67
9 .75
10 .83
11 .92

This calculator will help you determine the amount of square feet you have for replacing roof shingles. Roof shingles are figured by number of squares. 10'x10' = 100sf (1 square)

Roof Area Calculators: GABLE & HIPSHED
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. (If you do not know how to measure slope, see
these instructions.)

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.

A gable roof and a hip roof of the same length and slope will have identical areas.
Enter roof dimensions below for your roof in feet, (or slope as inches rise per foot.)
  • If you enter only L-1, W-1, & H-1, the result will be the area of a single straight gable roof.

  • If you enter all six values, the result will be the actual exposed area of both roofs. You cannot enter values for Area 2 alone.

  • The values calculated for roof 1 and roof 2 are independent. The total will not equal their added values, as the calculator subtracts the hidden area from roof 1 at the intersection, and displays only the actual exposed roof area for the total.
Area 1
= ft2
Total Exposed,
Areas 1& 2
Roof 1 Hidden
Roof 2 Ridge Length
L-2W-2 H-2slope2
Area 2
= ft2

Shed Roof:  
Gather the dimensions for your shed roof, and enter
below in feet, (or slope as inches rise per foot.)
Area 5
= ft2

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