How to Calculate Roof Pitch
What is Roof Pitch?
Roof Pitch Calculator helps contractors and tradespeople accurately size, spec, and estimate materials and systems.
Formula
Pitch = Rise / Run (in inches per 12 inches of run)
Step-by-Step Guide
- 1Measure vertical rise and horizontal run, express as X:12
- 2Apply the formula using your project measurements
- 3Add required safety factors or waste allowances per code
Worked Examples
Input
4 inches rise over 12 inches run
Result
Pitch = 4:12 (18.4° angle)
Common Mistakes to Avoid
- ✕Not applying code-required safety factors or derating
- ✕Forgetting to account for waste and cut losses in material estimates
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