PITCH & SLOPE REFERENCE TABLE
Roof Pitch Chart: Ratios, Degrees, Slope % & Multipliers
Use this definitive roof pitch and slope conversion chart to convert between standard $X/12$ pitch ratios, roof angles in degrees, slope grade percentages, and area pitch multipliers for all residential and commercial roof slopes.
How to Use This Chart
Find your roof pitch ratio in the left column. The chart provides the corresponding angle in degrees, slope grade percentage (useful for drainage and grading), and the exact pitch multiplier needed to multiply your building footprint into true sloped square footage.
| Pitch Ratio ($X/12$) | Angle (Degrees) | Slope Grade (%) | Pitch Multiplier | Walkability / Classification |
|---|---|---|---|---|
| 1/12 | $4.76^circ$ | 8.33% | 1.003 | Low Slope (Membrane Only) |
| 2/12 | $9.46^circ$ | 16.67% | 1.014 | Low Slope (Shingles w/ Double Felt) |
| 3/12 | $14.04^circ$ | 25.00% | 1.031 | Low Slope (Double Underlayment) |
| 4/12 | $18.43^circ$ | 33.33% | 1.054 | Moderate (Easily Walkable) |
| 5/12 | $22.62^circ$ | 41.67% | 1.083 | Moderate (Walkable) |
| 6/12 | $26.57^circ$ | 50.00% | 1.118 | Moderate (Standard Residential) |
| 7/12 | $30.26^circ$ | 58.33% | 1.158 | Moderate (Walkable with Care) |
| 8/12 | $33.69^circ$ | 66.67% | 1.202 | Moderate / Steep Transition |
| 9/12 | $36.87^circ$ | 75.00% | 1.250 | Steep (Harness Recommended) |
| 10/12 | $39.81^circ$ | 83.33% | 1.302 | Steep (Harness Required) |
| 11/12 | $42.51^circ$ | 91.67% | 1.357 | Steep (Harness & Jacks) |
| 12/12 | $45.00^circ$ | 100.00% | 1.414 | Steep ($45^circ$ True Diagonal) |
| 14/12 | $49.40^circ$ | 116.67% | 1.537 | Severe Steep |
| 16/12 | $53.13^circ$ | 133.33% | 1.667 | Severe Steep (Mansard/Gothic) |
| 18/12 | $56.31^circ$ | 150.00% | 1.803 | Severe Steep |
| 24/12 | $63.43^circ$ | 200.00% | 2.236 | Extreme Steep / A-Frame |
Trigonometric Conversion Formulas
Every value in the chart above is derived using standard right-triangle trigonometry where the horizontal run is 12 inches:
- Angle in Degrees: $theta = arctanleft(frac{text{Rise}}{12}right) times left(frac{180}{pi}right)$
- Slope Percentage: $text{Slope %} = left(frac{text{Rise}}{12}right) times 100$
- Pitch Multiplier: $M = sqrt{1 + left(frac{text{Rise}}{12}right)^2}$
Interactive Tool Available
Need to calculate a non-standard decimal pitch or dynamic roof area? Use our client-side Roof Pitch Calculator for instant geometric breakdown and dynamic SVG diagrams.
Frequently Asked Questions
What is a 6/12 pitch in degrees?
A 6/12 roof pitch equals exactly 26.57 degrees with a 50.0% slope grade and a pitch multiplier of 1.118.
What is the difference between roof pitch and slope percentage?
Roof pitch expresses vertical rise over a fixed 12-inch horizontal run ($X/12$), whereas slope percentage expresses rise over run as a percentage. A 12/12 pitch is a 100% slope grade ($45^circ$).