The calculation, explained.
The pitch area factor is √(1 + (rise/12)²). Apply it to horizontal plan area, then add the chosen allowance. One roofing square is 100 square feet; bundles round up using entered bundles per square.
Review the example assumptions and results
- Horizontal plan area
- 1200 ft²
- Rise per 12-inch run
- 6 in
- Extra material
- 10 %
- Bundles per square
- 3
- Estimated roof material
- 1475.8049 ft²
- Roofing squares
- 14.758
- Bundles
- 45
How this tool works
Adjust the labeled inputs to see a new calculation. Units and assumptions are shown beside each field. Printed and copied results use the same calculation.
This is a planning estimate, not a structural design, permit document or binding quote. Check product specifications and actual site measurements.
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