Roof Pitch Calculator
A roof pitch calculator finds the slope of your roof as a ratio (rise over run, like 6:12), as an angle in degrees, and as the area multiplier used to convert footprint to true roof area. Enter the rise and run (or the angle) below to get all three, so you can size roofing material correctly.
- Angle
- 26.6 degrees
- Area multiplier
- 1.118
6:12 pitch is about 26.6 degrees, with an area multiplier of 1.118.
How Do You Calculate Roof Pitch?
Roof pitch is expressed as the rise (vertical) over a 12 inch run (horizontal). To find it, measure how many inches the roof rises over 12 inches of horizontal distance: a roof that rises 6 inches per 12 is a 6:12 pitch. To get the angle, take the arctangent of rise divided by run. A 6:12 pitch is about 26.6 degrees. The calculator gives the ratio, the angle and the area multiplier together.
What Is the Roof Pitch Multiplier?
The pitch multiplier converts a roof's flat footprint area into its true sloped surface area. It is the square root of (rise squared plus run squared) divided by run. For a 6:12 pitch the multiplier is about 1.12, so the real roof area is 12 percent larger than the footprint. This number is essential for ordering roofing, because you cover the slope, not the ground outline below it.
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Frequently asked questions
- How do I calculate roof pitch?
- Measure the rise over a 12 inch run. A roof rising 6 inches per 12 is a 6:12 pitch, about 26.6 degrees. The calculator also gives the area multiplier.
- What is the roof pitch multiplier?
- It converts footprint area to true sloped area. A 6:12 pitch multiplier is about 1.12, meaning the real roof is 12 percent larger than the footprint.