Sqratch Tools / Structural & Shell / Roof Pitch & Rafter Calculator
Roof Pitch & Rafter Calculator
Calculate exact roof pitch, angle in degrees, and rafter lengths for symmetrical gable roofs.
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Basis & Assumptions
- Rafter length is the hypotenuse of the total run (half-span + overhang) and total rise (rise + pitch-adjusted overhang).
- Calculations represent theoretical geometric lines — actual rafter cut lengths depend on birdsmouth cuts and ridge board thickness.
For quick design checks and study — not a substitute for your local Development Control Regulations, NBC provisions, or a licensed professional's judgement. Always verify against the bye-laws that apply to your site.
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