Rafter rise run from the pythagorean theorem.
How to find degree of slope on roof.
If you do know the roof slope in degrees then all you have to do is find the secant using a scientific calculator.
How do you calculate the slope of a roof.
Rise run pitch where pitch is expressed in percent.
But you still need to have the rise and the run to find the degree angle if you don t already know it.
A 4 in 12 pitch becomes 4 12 then divide.
Next find the degrees by finding the arc tangent of the slope eg.
Access one of the rafters then take.
For the complementary angle reverse the rise and run.
To put it in perspective the angle of this slope would be around 30 degrees.
Let s find the angle in degrees for a roof with a 4 in 12 pitch.
The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.
4 12 4 12 333.
This is our pitch calculator which will convert pitch to angle or angle to pitch for half degree roof slope calculations.
How to calculate roof pitch.
Degrees atan slope.
This means that the rise of the slope goes up or down 8 inches for every 12 inches.
Pitch tan angle where angle is the roof pitch expressed in degrees.
With the use of this converter it will be easier for you to locate a 30 degree roof pitch 20 degree roof pitch 25 degree roof pitch or a 15 degree roof pitch.
For a pitch expressed in inches per foot convert to a fraction first eg.
That page also explains the math that allows you to do the conversions yourself for any slope not listed.
Locate the level s 12 inch mark.
Use a level against the underside of the rafter you re measuring to get the most accurate value.
Roof slope expressed as rise.
To find the slope in degrees you divide the rise by the run and find the inverse tangent of the result.
However if you to do the process using your own knowledge you can still convert pitch to degrees by dividing the rise and run and get its corresponding measurement.
The most precise way to find the roof s slope is by measuring it from the underside.
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.
The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches.
Enter any pitch or fraction of pitch to find angle.
An example for a steep sloped roof is 8 12.