Roof Pitch Calculator
Roof Pitch Calculator
Calculate roof pitch, angle, and rafter length for your roofing projects
Calculation Results
Pitch Ratio:
0:12
Roof Angle:
0°
Pitch Percentage:
0%
Rafter Length:
0 ft
Rafter Length (with overhang):
0 ft
Roof Diagram
Common Roof Pitches Reference
| Pitch (X:12) | Angle | Percentage | Common Use |
|---|---|---|---|
| 2:12 | 9.46° | 16.67% | Low slope roofs |
| 4:12 | 18.43° | 33.33% | Common residential |
| 6:12 | 26.57° | 50% | Typical roof |
| 8:12 | 33.69° | 66.67% | Steep roof |
| 12:12 | 45° | 100% | Very steep |
About Roof Pitch
Roof pitch is the steepness of a roof expressed as a ratio of vertical rise to horizontal run. For example, a 4:12 pitch means the roof rises 4 inches for every 12 inches of horizontal run.
Pitch Ratio = Rise : Run
Angle = arctan(Rise / Run)
Percentage = (Rise / Run) × 100%
Rafter Length = √(Rise² + Run²)
Angle = arctan(Rise / Run)
Percentage = (Rise / Run) × 100%
Rafter Length = √(Rise² + Run²)
How to Use This Calculator
1. Choose your preferred input method (Pitch Ratio, Angle, or Rise & Run)
2. Enter the required values
3. Optionally enter roof span and overhang for rafter length calculations
4. Click "Calculate" to see all roof measurements
Roof Pitch Categories
- Flat/Low Slope: 0:12 to 2:12 (0° to 9.5°)
- Conventional: 4:12 to 9:12 (18.5° to 37°)
- Steep Slope: 10:12 to 21:12 (40° to 60°)

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