Determine roof pitch in degrees, percentage, slope ratio, and pitch factor. Select from common presets or enter custom rise and run values.
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Common Pitches
4
Output Formats
2
Systems
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Select a pitch preset or enter custom rise/run to see your roof pitch results.
Roof Pitch
0/12
Angle in Degrees
0°
Slope Percentage
0%
Slope Ratio
0:1
Pitch Factor
0
Rafter Length
0 in/ft
Calculation Summary
Pitch (Rise/Run)0 / 12
Angle0°
Slope Percentage0%
Pitch Factor0
Rafter per Foot of Run0 in
Frequently Asked Questions
Roof pitch is expressed as rise over run, typically in inches per 12 inches of horizontal run. For example, a 6/12 pitch means the roof rises 6 inches for every 12 inches of horizontal distance.
While often used interchangeably, pitch traditionally refers to the ratio of rise to total span, while slope refers to rise per unit run. In modern construction, "pitch" commonly means slope expressed as rise/12.
Use the formula: angle = arctan(rise / run). For a 6/12 pitch: arctan(6/12) = 26.57°. A 12/12 pitch equals 45°.
The pitch factor (also called the roof multiplier) is calculated as √((rise/run)² + 1). It is used to multiply the horizontal roof area to get the actual sloped surface area. For a 6/12 pitch, the factor is approximately 1.118.
Rafter length per foot of run equals √(rise² + run²) / run. For a 6/12 pitch, each foot of horizontal run requires approximately 13.42 inches of rafter length.
The most common residential roof pitch is 6/12, offering a good balance of water shedding capability, aesthetic appeal, and walkability. Pitches between 4/12 and 9/12 are standard for most homes.