Roofing Calculator
Estimate roof squares, roof area and approximate bundle count from plan dimensions and pitch.
Project inputs
Enter your measurements. Results update automatically.
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See estimating toolsEstimate roof area, squares and bundles
This roofing calculator starts with building plan dimensions and a roof-pitch rise. It applies a pitch factor to estimate sloped roof area, converts the area to roofing squares, then adds your waste allowance and estimates bundles using the bundles-per-square value you enter.
Roofing squares
One roofing square represents 100 square feet of roof area. Estimated roof area is divided by 100 before the waste allowance is applied.
Pitch factor
The calculator uses the entered rise over a 12-inch run to increase plan area for slope. Use roof-plan dimensions that include overhangs for a better estimate.
What is not included
Valleys, hips, dormers, starter shingles, ridge cap, underlayment, flashing and specialty details require separate takeoff. Complex roofs should be measured by roof plane instead of treated as one simple rectangle.
Common roofing calculator questions
How many square feet are in a roofing square?
One roofing square equals 100 square feet of roof surface.
Why is waste adjustable?
Roof complexity, valleys, hips and cut patterns can change waste significantly, so a fixed percentage is not appropriate for every roof.
How many bundles are in a square?
That varies by shingle product. Enter the bundles-per-square value for the roofing product you plan to use.