Roof Pitch Calculator
Calculate roof pitch, slope, angle, and rafter length. Convert between pitch ratios, degrees, and percentages for roofing projects.
Step 1: Roof Measurements
Common Roof Pitches
Low slope: 2:12 to 4:12. Conventional: 4:12 to 9:12. Steep slope: 9:12 to 12:12+. Flat roofs: 0:12 to 2:12.
Step 2: Calculation Options
Roof Pitch Formula
Pitch = Rise ÷ Run × 12. Angle = arctan(Rise/Run). Percentage = (Rise/Run) × 100%. Rafter = √(Rise² + Run²).
Roof Pitch Calculation Results
Summary
Conversions
Roofing Applications
Roof Pitch
4:12
18.43° angle | 33.33% slope
Roof Pitch Visualization
▲
Rise: 6″
Run: 12″
Pitch: 4:12
Rise: 6″
Run: 12″
Pitch: 4:12
Rafter Length
13.42 ft
Roof Angle
18.43°
Slope Percentage
33.33%
Roof Area (100 ft²)
268.3 ft²
Pitch Conversion Table
| Pitch Ratio | Angle (°) | Percentage | Rise per 12″ | Roof Type |
|---|
Conversion Formulas
Degrees = arctan(Rise/Run). Percentage = (Rise/Run) × 100. Ratio = Rise:12 (standard). 1:12 = 4.76° = 8.33%.
Roofing Material Applications
Recommended Materials by Pitch
| Pitch Range | Recommended Materials | Minimum Pitch | Typical Use |
|---|---|---|---|
| 0:12 to 2:12 | Built-up roofing, EPDM, TPO | 0.25:12 | Flat/Commercial roofs |
| 2:12 to 4:12 | Asphalt shingles (special underlayment) | 2:12 | Low-slope residential |
| 4:12 to 9:12 | Standard asphalt shingles | 4:12 | Conventional roofs |
| 9:12 to 12:12+ | Shingles with special fastening, metal roofing | 3:12 | Steep roofs |
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