Construction Tool Roof Pitch Calculator Quickly convert structural rise and run metrics into standard grade percentage angles and ratio pitches.
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Understanding Ratios and Slopes
In traditional building systems, roof slope is represented as an index fraction matching X inches of vertical rise per every 12 inches of horizontal run. In engineering fields, this is tracked as a strict geometric angle or tangent gradient percentage.
Angle = arctan(Rise / Run)
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Slope Metrics
in/cm
in/cm
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Slope Conversions
Imperial Pitch Index
Slope Angle
Grade Percentage
Roof pitches below 2:12 ratio indexes require specialty water-impermeable single-ply membrane flat sheet flashing setups.