Roof Pitch Chart: Slope, Angle Degrees, and Multipliers
A complete roof pitch chart converting rise-over-run ratios into angles in degrees, percentages, and slope factor multipliers for square footage estimation.
Understanding roof pitch is critical for any roofing project, whether you are calculating squares for shingles, framing rafters, or estimating structural load. Roof pitch represents the slope or steepness of your roof, traditionally expressed as a ratio of vertical rise to horizontal run.
Use this ultimate Roof Pitch Chart to easily convert common pitch ratios into slope degrees, percentages, and area multipliers.
What is Roof Pitch? (Rise over Run)
In the United States, roof pitch is expressed as a fraction: Rise / Run.
- Rise: The vertical height the roof climbs.
- Run: The horizontal distance the roof extends (standardized at 12 inches).
Therefore, a "6/12 pitch" means the roof rises 6 vertical inches for every 12 horizontal inches.
The Master Roof Pitch Chart
Use the reference table below to convert any standard roof pitch into degrees, grade percentage, and its corresponding slope factor (used for square footage math).
| Roof Pitch Ratio | Angle (Degrees) | Angle (Percentage) | Slope Factor (Multiplier) | Walks status |
|---|---|---|---|---|
| 0/12 (Flat) | 0.00° | 0.0% | 1.000 | Safe / Walkable |
| 1/12 (Low) | 4.76° | 8.3% | 1.003 | Safe / Walkable |
| 2/12 | 9.46° | 16.7% | 1.014 | Walkable |
| 3/12 | 14.04° | 25.0% | 1.031 | Walkable |
| 4/12 (Standard) | 18.43° | 33.3% | 1.054 | Walkable |
| 5/12 | 22.62° | 41.7% | 1.083 | Walkable |
| 6/12 (Moderate) | 26.57° | 50.0% | 1.118 | Walkable (Take Care) |
| 7/12 | 30.26° | 58.3% | 1.158 | Walkable (Steep) |
| 8/12 (Steep) | 33.69° | 66.7% | 1.202 | Non-Walkable (Jacks) |
| 9/12 | 36.87° | 75.0% | 1.250 | Non-Walkable |
| 10/12 | 39.81° | 83.3% | 1.302 | Non-Walkable |
| 11/12 | 42.51° | 91.7% | 1.357 | Non-Walkable |
| 12/12 (45° Angle) | 45.00° | 100.0% | 1.414 | Non-Walkable |
| 15/12 | 51.34° | 125.0% | 1.601 | Extreme Slope |
| 18/12 | 56.31° | 150.0% | 1.803 | Extreme Slope |
How to Use the Slope Factor Multiplier
The Slope Factor column in the chart is a powerful shortcut. You can find the true surface area of a sloped roof without stepping onto a ladder:
- Calculate the flat footprint area of the house (Length × Width, including overhangs).
- Look up the slope factor for your roof pitch in the chart.
- Multiply the footprint area by the slope factor.
Worked Example:
If your home has a flat footprint of 1,800 sq ft under a roof with a 6/12 pitch:
Sloped Area = 1,800 sq ft × 1.118 = 2,012.4 sq ft
Convert this to roofing squares by dividing by 100:
Roofing Squares = 2,012.4 ÷ 100 = 20.12 squares
How to Determine Your Roof Pitch
There are three common ways to measure your pitch:
1. From the Attic rafters
Measure from the inside of your attic by placing a level against the underside of a rafter. Measure 12 inches along the level horizontally (run), and then measure vertically from the 12-inch mark up to the rafter (rise).
2. From the Roof surface
Place a 12-inch level flat against the roof surface. Hold it perfectly level, then measure the vertical distance from the end of the level down to the shingles.
3. From the Ground
Use a smartphone app or stand back and take a photo of the gable end. You can use our Roof Pitch Calculator to compute slope angles from ground-level dimensions.
Frequently Asked Questions
What is a standard roof pitch for residential homes?
Most residential homes feature a roof pitch between 4/12 and 9/12. A 4/12 pitch is standard and walkable, rising 4 inches per foot. Pitches above 9/12 are steep-slope and require specialized safety equipment.
How do you convert roof pitch to degrees?
To convert roof pitch to degrees, find the inverse tangent of the rise divided by the run: Angle = arctan(Rise / Run) * (180 / pi). For example, a 6/12 pitch has a rise-to-run ratio of 0.5, which converts to 26.57 degrees.
What is a slope factor or pitch multiplier?
A slope factor is a multiplier used to calculate sloped roof area from flat footprint area. It represents the hypotenuse of the rise-run triangle. Multipliers range from 1.014 for low 2/12 pitch to 1.414 for steep 12/12 pitch.
What is the minimum pitch for standard shingles?
Standard asphalt shingles require a minimum pitch of 2/12. For pitches between 2/12 and 4/12, installers must apply double-layered underlayment. Anything below 2/12 requires a low-slope membrane like EPDM or TPO.
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