Roof pitch calculator
Measure how far the roof rises over a level run, in any unit. A roof that rises 6 inches over 12 inches of run is a 6/12 pitch: 26.6°, a 50% slope.
Pitch
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Angle
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Slope
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Area multiplier
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How it works
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Pitch is rise per 12 units of run. The angle is the arctangent of rise ÷ run, and the slope percentage is rise ÷ run × 100. The multiplier tells you how much bigger the sloped roof surface is than its flat footprint; the roofing calculator uses it to estimate squares and bundles.
Pitch to angle chart
| Pitch | Angle | Slope | Multiplier |
|---|---|---|---|
| 1/12 | 4.8° | 8.3% | 1.003 |
| 2/12 | 9.5° | 16.7% | 1.014 |
| 3/12 | 14.0° | 25.0% | 1.031 |
| 4/12 | 18.4° | 33.3% | 1.054 |
| 5/12 | 22.6° | 41.7% | 1.083 |
| 6/12 | 26.6° | 50.0% | 1.118 |
| 7/12 | 30.3° | 58.3% | 1.158 |
| 8/12 | 33.7° | 66.7% | 1.202 |
| 9/12 | 36.9° | 75.0% | 1.250 |
| 10/12 | 39.8° | 83.3% | 1.302 |
| 11/12 | 42.5° | 91.7% | 1.357 |
| 12/12 | 45.0° | 100.0% | 1.414 |
Low and steep roofs
Very low pitches shed water slowly, so many shingle products have a minimum pitch and extra underlayment rules below a certain slope. Steep roofs need more safety equipment to work on. Check the installation instructions for the roofing product you plan to use.