Roof Pitch Calculator: Angle & Rafter Length
Find the roof pitch, angle, and rafter length.
Understanding Roof Pitch
Roof pitch is the steepness of a roof expressed as a ratio of vertical rise to horizontal run. In the US, it is typically displayed as inches of rise per 12 inches of run (e.g., 4/12).
How to Measure Pitch
- Mark a level at 12 inches.
- Hold the level perfectly horizontal against the roof slope.
- Measure the vertical distance from the roof to the 12-inch mark on your level.
- That measurement is your 'Rise' (e.g., if it's 6 inches, your pitch is 6/12).
Roofing FAQs
What is a standard roof pitch?
Standard residential roofs often range from 4/12 to 9/12. Anything below 2/12 is considered a flat roof.
How do I calculate rafter length?
Rafter length is the hypotenuse of the triangle formed by the rise and run. You can use the Pythagorean theorem (a² + b² = c²) to find it.