Roof Pitch Calculator
Convert rise and run into pitch, angle, and slope factor.
Pitch
6 / 12
Conventional — walkable with care
Angle
26.6°
Slope factor
1.118
Pitch in carpenter's units
Roofers quote inches of rise per 12 of run: 6/12 is 26.6°. The slope factor √(1 + (rise/run)²) converts the house footprint to true roof area — a 6/12 roof has 12% more surface than its footprint, which is 12% more shingles.
Pitch drives everything
Below 2/12, shingles leak and membranes take over; 4/12–9/12 is the conventional shingle zone; steeper sheds snow brilliantly but multiplies labor cost. Measure pitch with a level and a ruler: inches of rise under a 12-inch level held horizontal.
Frequently asked questions
- How does the Roof Pitch Calculator work?
- Convert rise and run into pitch, angle, and slope factor.
- Is the Roof Pitch Calculator free to use?
- Yes. The Roof Pitch Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
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