Convert Roof Angle (Degrees) to Rise-in-Run
Roof Online Staff
The following table shows the roof pitch (rise-in-run) equivalents for all roof slopes in degrees from 1° to 72°. Other than the 45° roof slope, which is 12-in-12, none of the standard roof pitches (5-in-12, 6-in-12, etc.) are equal to a whole degree.
To see what the degree equivalents are for standard rise-in-run roof pitches, see our page, Quick Reference: Roof Slope Expressed as Rise : Run, Degrees, Percentage. That page also explains the math that allows you to do the conversions yourself for any slope not listed.
To Convert Slopes of fractional degrees to Rise-in-Run: Find the tangent of the degree value. Multiply the tangent by the run (which is by convention always 12). That gives you the rise. Put them together as Rise-in-Run.
Example: For a slope of 35.5°,
tan(35.5) = 0.713
0.713 x 12 = 8.556
giving you a slope of 8.556-in-12 or
approximately 8-9/16 in 12.
If you’re not sure what the slope of your roof is and you want to determine that in either degrees or rise-in-run, we recommend this slope finder on Amazon.* It’s very inexpensive and very accurate.
If you’re using this table, you may want to look into getting yourself a construction calculator. This one is very good.*