Roof Pitch Chart: Angle, Degrees & Slope Multiplier
Part of Decks, Fences & Roofing
Quick answer
A roof pitch chart converts the rise-in-12 pitch to an angle and a slope multiplier. Common examples: 4-in-12 = 18.4° (1.054×), 6-in-12 = 26.6° (1.118×), 9-in-12 = 36.9° (1.25×), 12-in-12 = 45° (1.414×). Multiply your roof's footprint area by the slope multiplier to get the actual roof surface area.
Every roof pitch maps to a fixed angle and a fixed slope multiplier. The multiplier is the key number for ordering material: it's how much bigger the sloped roof is than the flat area underneath it.
Roof pitch conversion chart
| Pitch | Angle | Grade | Slope multiplier |
|---|---|---|---|
| 2-in-12 | 9.5° | 16.7% | 1.014 |
| 3-in-12 | 14.0° | 25% | 1.031 |
| 4-in-12 | 18.4° | 33.3% | 1.054 |
| 5-in-12 | 22.6° | 41.7% | 1.083 |
| 6-in-12 | 26.6° | 50% | 1.118 |
| 7-in-12 | 30.3° | 58.3% | 1.158 |
| 8-in-12 | 33.7° | 66.7% | 1.202 |
| 9-in-12 | 36.9° | 75% | 1.250 |
| 10-in-12 | 39.8° | 83.3% | 1.302 |
| 12-in-12 | 45° | 100% | 1.414 |
Using the slope multiplier
- Find the footprint: the flat area the roof covers (length × width of the building plus overhangs).
- Multiply the footprint by the slope multiplier for your pitch to get the actual roof surface area.
- Divide by 100 to get roofing 'squares' (1 square = 100 ft²), then add 10–15% for waste, hips and valleys.
Don't want to read off the chart? The roof pitch calculator returns the exact angle, grade and slope multiplier for any rise and run, including odd pitches the chart skips.
FAQs
How do I convert roof pitch to degrees?
Take the arctangent of the rise divided by the run. For a 6-in-12 pitch that's arctan(6 ÷ 12) = 26.57°. The chart above lists the common pitches, or the calculator does it for any rise/run.
What is the roof slope multiplier?
It's √(rise² + run²) ÷ run — how much longer the slope is than the flat run. A 6-in-12 roof has a 1.118 multiplier, so its surface area is 11.8% larger than the footprint it covers.