Roof pitch
- Degrees
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- Rafter
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About this roof pitch calculator
Relate rise, run, and pitch angle or “x/12” pitch so you can move between the common ways framers and permits talk about slope.
Pitch ratio and angle come from right-triangle trig: angle = arctan(rise/run); x/12 scales the same slope. Hypotenuse / rafter length uses Pythagoras when those fields are on the form.
Not a structural design tool, snow-load check, or cutting list. Local code and a licensed pro own safety-critical framing decisions.
What is roof pitch?
Rise over run, usually written as N:12. Type degrees from a phone inclinometer and rise/run follow.
How are degrees calculated?
The arctangent of rise divided by run, in degrees. Going the other way, rise is run times the tangent of the angle. Going the other way, rise is run times the tangent of the angle.
What is rafter length here?
The straight-line length for that rise and run (the hypotenuse). Same units as the inputs.
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