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Roof MeasurementsEave to eave (longest horizontal dimension)
Ridge to eave (measured along the slope, or we calculate from pitch)
Pitch multiplier applied to footprint for actual roof area
Length of peak (usually = roof length for gable)
Affiliate Disclosure: This calculator is free to use. Some product links are affiliate links. Product links and pricing are for the US market.
How This Calculator Works
- Roofing square: 1 square = 100 sq ft of roof area. Shingles are sold by the bundle (3 bundles per square for standard shingles).
- Pitch multiplier: A 4/12 pitch roof has 6% more surface area than its footprint. A 12/12 pitch (45 degrees) has 41% more. The calculator adjusts for this automatically.
- 10% waste: Standard waste factor for a simple gable roof. Complex roofs with hips, valleys, and dormers waste 15-20%. Adjust by adding extra squares if your roof is complex.