Full 0:12 to 24:12 Pitch Conversion Matrix
Use this table to translate architectural plans, convert degrees to pitch for lumber orders, or calculate rafter lengths with the multiplier factor.
| Pitch (X:12) | Degrees (°) | Slope % | Multiplier | Typical Roofing Material | Walkability & Safety |
|---|---|---|---|---|---|
| 0:12 | 0.00° | 0.00% | 1.0000 | Single-ply EPDM, TPO, Built-Up | Completely Flat (Easy) |
| 1:12 | 4.76° | 8.33% | 1.0035 | Standing Seam Metal, Membrane | Easy (Slight Slope) |
| 2:12 | 9.46° | 16.67% | 1.0138 | Double-underlayment Shingles, Metal | Easy Walkable |
| 3:12 | 14.04° | 25.00% | 1.0308 | Double-underlayment Shingles, Metal | Easy Walkable |
| 4:12 | 18.43° | 33.33% | 1.0541 | Standard Shingles, Metal, Tiles | Walkable with caution |
| 5:12 | 22.62° | 41.67% | 1.0833 | Standard Shingles, Tile, Shakes | Walkable for experienced |
| 6:12 | 26.57° | 50.00% | 1.1180 | All Standard Residential Materials | Walkable with soft shoes |
| 7:12 | 30.26° | 58.33% | 1.1577 | Asphalt, Wood Shakes, Standing Seam | Steep; boots recommended |
| 8:12 | 33.69° | 66.67% | 1.2019 | Asphalt, Slate, Metal, Tiles | Very steep; toe boards |
| 9:12 | 36.87° | 75.00% | 1.2500 | Architectural Shingles, Slate, Metal | Fall harness required |
| 10:12 | 39.81° | 83.33% | 1.3017 | Slate, Tile, Architectural Shingles | Unwalkable; roof jacks |
| 11:12 | 42.51° | 91.67% | 1.3566 | Slate, Cedar Shakes, Metal | Unwalkable; roof jacks |
| 12:12 | 45.00° | 100.00% | 1.4142 | All steep-slope materials | True 45°; ropes mandatory |
| 14:12 | 49.40° | 116.67% | 1.5374 | Victorian, Alpine, Steep Slate | Unwalkable scaffold only |
| 16:12 | 53.13° | 133.33% | 1.6667 | A-Frames, Mansards, Steep Gables | Unwalkable scaffold only |
| 18:12 | 56.31° | 150.00% | 1.8028 | Gothic, Alpine A-Frames | Unwalkable scaffold only |
| 24:12 | 63.43° | 200.00% | 2.2361 | Mansard vertical sides, Steeples | Vertical wall staging |
How to Use the Multiplier Column
Multiply your building horizontal run (or flat footprint area) by the multiplier number to obtain the true sloped rafter line length (or true sloped roof surface area).
Safety Walkability Notice
Pitches steeper than 6:12 should not be walked without fall protection equipment. Pitches of 8:12 and above require roof jacks, toe boards, and OSHA harnesses.