Roofing calculator
Roof Square Footage Calculator
Calculate roof square footage from building footprint and roof pitch.
Your measurements
Estimated result
Plan area0 sq ft
Slope factor1.118
Sloped roof area0 sq ft
With waste0 sq ft
Planning estimate only. Check product specifications, site conditions and local codes before ordering or building.
Roof area formula
Sloped roof area = horizontal plan area × slope factor. For an x:12 pitch, slope factor = √(x² + 12²) ÷ 12.
Planning notes
This method works best for simple roof geometry. Overhangs, hips, valleys, dormers and intersecting roof sections need separate measurements for a reliable material takeoff.
- This is a quick estimate for simple roof geometry.
- Hips, valleys, dormers and overhangs need more detailed measurements.
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