Roof Pitch
6.00 : 12
Angle
26.57°
Pitch Type
Low Slope
Inputs
Result
Pitch = 6/12 = 0.5. Angle = arctan(0.5) × 180/π = 26.57°. Slope = 0.5 × 100 = 50%. Multiplier = √(1 + 0.25) = 1.118.
Inputs
Result
Pitch = 10/12 = 0.833. Angle = arctan(0.833) × 180/π = 39.81°. Slope = 0.833 × 100 = 83.3%. Multiplier = √(1 + 0.694) = 1.302.
The most common roof pitches are 4/12 to 9/12. A 4/12 pitch (18.4°) is the minimum for standard shingles. Most residential roofs use 6/12 (26.6°) to 8/12 (33.7°). Steeper pitches shed water and snow better but cost more.
| Pitch | Degrees | Multiplier | Category |
|---|---|---|---|
| 2/12 | 9.5° | 1.014 | Low slope (needs membrane roofing) |
| 4/12 | 18.4° | 1.054 | Min for shingles |
| 6/12 | 26.6° | 1.118 | Standard residential |
| 8/12 | 33.7° | 1.202 | Moderate steep |
| 10/12 | 39.8° | 1.302 | Steep – safety gear needed |
| 12/12 | 45.0° | 1.414 | Very steep – scaffolding required |
Roof pitch = Rise ÷ Run, expressed as X:12. Measure the vertical rise in inches over a 12-inch horizontal run. For example, if the roof rises 6 inches for every 12 inches of run, the pitch is 6:12 (26.6 degrees).
The roof pitch multiplier converts flat area to actual roof area. Formula: √(1 + (pitch/12)²). For a 6/12 pitch, multiplier = √(1 + 0.25) = 1.118. Multiply flat footprint area by this factor to get actual roof area for materials.
| Pitch | Multiplier | 1,500 sq ft Footprint | Extra Material vs. Flat |
|---|---|---|---|
| 4/12 | 1.054 | 1,581 sq ft | +5.4% |
| 6/12 | 1.118 | 1,677 sq ft | +11.8% |
| 8/12 | 1.202 | 1,803 sq ft | +20.2% |
| 10/12 | 1.302 | 1,953 sq ft | +30.2% |
| 12/12 | 1.414 | 2,121 sq ft | +41.4% |
Most roofers consider pitches above 8/12 (33.7°) difficult to walk on and above 10/12 (39.8°) requires special safety equipment. Pitches over 12/12 (45°) are very steep and require scaffolding or roof jacks.
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Last Updated: Mar 9, 2026
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