Verified Mathematical Model & Formulation
Pitch = Rise / Run (standardized to :12) Angle (°) = arctan(Rise / Run) × (180 / π) Pitch Multiplier = √(1 + (Rise / Run)²)
Calculates the slope geometry using trigonometric tangent relationships and Pythagorean theorem to find the rafter factor/pitch multiplier.
Configurable Parameters & Standard Units
- Vertical Rise: (Default: 6 in)
- Horizontal Run: (Default: 12 in)
Standard Worked Example & Practical Verification
Scenario: A roof rises 6 inches vertically for every 12 inches of horizontal span.
Calculated Solution
6:12 Pitch (26.57° Slope, 1.118 Multiplier)
Practical Takeaway: Multiply your home’s flat footprint square footage by 1.118 to calculate actual sloped roof surface.
Frequently Asked Questions
What is a low pitch roof?
Pitches below 4:12 are considered low slope and often require double underlayment or specialized membrane systems instead of standard asphalt shingles.