About the Slope Conversion Table
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 or percentage equivalents are for standard rise-in-run roof pitches, see our page 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.
Conversion Formula for Degrees to Standard Roof Pitch
To convert slopes in degrees, including slopes that include a fraction of a degree, to standard roof pitch:
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.
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.
Roof Slope in Degrees to Standard Roof Pitch Conversion Tables
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.*