Roof Pitch Calculator
Roof pitch decides what materials you can use, and how much you need. Enter rise and run to get the pitch ratio in X:12 notation, the angle in degrees, and the multiplier you apply to your plan area to get actual roof area.
Results
Enter your measurements above and press Calculate.
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Questions people ask
What does a 6/12 roof pitch mean?
The roof rises 6 inches for every 12 inches of horizontal run. That is 26.6 degrees. Over a 12 foot run it rises 6 feet.
How do I calculate roof area?
Take the horizontal footprint of the building, multiply by the pitch multiplier. A 6:12 pitch multiplies area by 1.118, so 1,000 square feet of plan area needs about 1,118 square feet of roof.
What is the minimum roof pitch for shingles?
Architectural asphalt shingles need at least a 2:12 pitch. Standard three-tab shingles need 4:12. Metal roofing can go as low as 1:12 with sealant. Below 2:12 use a roll membrane roof instead.
Is a steeper roof more expensive?
Yes — more area means more material, and steep roofs need more underlayment and ventilation. A 10:12 pitch uses about 30 percent more roofing than a flat roof over the same footprint.
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