Roof Area Calculator
Calculate your roof area and estimate how many bundles of shingles you need based on building dimensions and roof pitch.
Roof Area & Materials
Roof Area depends on the footprint of the building and the roof pitch. A steeper pitch means more roof surface area.
Roof Area = Building Length × Building Width × Pitch Multiplier
Pitch multipliers (rise per 12 inches of run):
- 4/12 pitch: 1.054
- 6/12 pitch: 1.118
- 8/12 pitch: 1.202
- 10/12 pitch: 1.302
- 12/12 pitch: 1.414
Shingle bundles:
- 3 bundles typically cover 1 square (100 sq ft / 9.29 m²)
Bundles = (Roof Area / 100) × 3(imperial)Bundles = (Roof Area / 9.29) × 3(metric)
Imperial: Length and width in feet, area in square feet. Metric: Length and width in meters, area in square meters.
Always order 10–15% extra for waste, cuts, and ridges.