How we worked it out
Updated as you change the numbers.
- Pitch = rise ÷ run × 12. Angle = arctan(rise ÷ run).
- Area factor = √(1 + (rise ÷ run)²), the rafter length per unit of run.
Method and assumptions
Shingle makers generally require a pitch of at least 2/12, with extra underlayment below 4/12. Check the product’s instructions and local code.
Questions
What angle is a 6/12 roof pitch?
26.57°, a 50% slope; roof area is 1.118 times the footprint.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.