Roof Pitch Calculator
Calculate roof pitch from rise and run. Get the angle in degrees, pitch ratio (e.g., 6:12), and slope percentage.
How to Calculate Roof Pitch
Angle = arctan(Rise ÷ Run) × (180 ÷ π)
Slope % = (Rise ÷ Run) × 100
Rafter Length = √(Rise² + Run²)
Roof pitch is typically expressed as a ratio of rise to run where run is standardized at 12 inches. A "6:12 pitch" means the roof rises 6 inches for every 12 inches of horizontal run.
Rise = 6 inches, Run = 12 inches
Pitch = 6:12
Angle = arctan(6/12) = 26.57°
Slope = (6/12) × 100 = 50%
Rafter = √(36+144) = 13.42 inches per 12" run
Common Roof Pitches
Low slope: 2:12 to 4:12 (suitable for rolled roofing). Medium: 4:12 to 9:12 (standard shingles). Steep: 9:12 to 12:12 (enhanced drainage, more complex framing).
Minimum Pitch by Roofing Material
Asphalt shingles: 2:12 minimum | Metal roofing: 3:12 | Cedar shakes: 4:12 | Flat/membrane: ¼:12
FAQ
What is the most common roof pitch?
4:12 to 6:12 is most common for residential homes. These pitches provide good drainage while keeping material and labor costs manageable.
How does pitch affect roofing cost?
Steeper roofs (above 6:12) require additional safety equipment, increase labor time, and use more material due to the greater surface area.
Last updated: 2026-08-08