Roof Pitch Multiplier Table: Complete Reference
The pitch multiplier converts your building's flat footprint area into the actual sloped roof area. Essential for ordering the correct amount of roofing materials.
How to Use This Table
Actual Roof Area = Footprint Area x Pitch Multiplier
Example: 1,500 sq ft footprint x 1.118 (6/12 pitch) = 1,677 sq ft roof area
Complete Pitch Multiplier Table
| Pitch | Degrees | Multiplier | % Increase | Category |
|---|---|---|---|---|
| 0/12 | 0.0 | 1.000 | 0% | Flat |
| 0.5/12 | 2.4 | 1.001 | 0.1% | Flat |
| 1/12 | 4.8 | 1.003 | 0.3% | Low slope |
| 2/12 | 9.5 | 1.014 | 1.4% | Low slope |
| 3/12 | 14.0 | 1.031 | 3.1% | Moderate |
| 4/12 | 18.4 | 1.054 | 5.4% | Moderate |
| 5/12 | 22.6 | 1.083 | 8.3% | Standard |
| 6/12 | 26.6 | 1.118 | 11.8% | Standard |
| 7/12 | 30.3 | 1.158 | 15.8% | Standard |
| 8/12 | 33.7 | 1.202 | 20.2% | Standard |
| 9/12 | 36.9 | 1.250 | 25.0% | Steep |
| 10/12 | 39.8 | 1.302 | 30.2% | Steep |
| 11/12 | 42.5 | 1.357 | 35.7% | Steep |
| 12/12 | 45.0 | 1.414 | 41.4% | Very steep |
| 13/12 | 47.3 | 1.474 | 47.4% | Very steep |
| 14/12 | 49.4 | 1.537 | 53.7% | Very steep |
| 15/12 | 51.3 | 1.601 | 60.1% | Very steep |
| 16/12 | 53.1 | 1.667 | 66.7% | Extreme |
| 17/12 | 54.8 | 1.734 | 73.4% | Extreme |
| 18/12 | 56.3 | 1.803 | 80.3% | Extreme |
| 19/12 | 57.7 | 1.873 | 87.3% | Extreme |
| 20/12 | 59.0 | 1.944 | 94.4% | Extreme |
| 21/12 | 60.3 | 2.016 | 101.6% | Extreme |
| 22/12 | 61.4 | 2.088 | 108.8% | Extreme |
| 23/12 | 62.4 | 2.162 | 116.2% | Extreme |
| 24/12 | 63.4 | 2.236 | 123.6% | Extreme |
Visual: How Pitch Affects Roof Area
Bar width represents the percentage increase in roof area compared to the flat footprint.
The Math Behind the Multiplier
Multiplier = sqrt(1 + (Rise/12)^2)
Example for 6/12: sqrt(1 + (6/12)^2) = sqrt(1 + 0.25) = sqrt(1.25) = 1.118
Practical Applications
Calculate roof area
Footprint x multiplier = roof area. See our roof area guide.
Calculate rafter length
Run x multiplier = rafter length (slope distance). See our rafter length guide.
Estimate materials
Accurate roof area leads to accurate material orders. Use our Shingle Calculator.
For automatic calculations using these multipliers, try our Roof Pitch Calculator, which converts between pitch, degrees, and multipliers instantly.