Roofers
Roof Pitch Calculator
Convert roof rise and run to pitch ratio, angle in degrees, and slope multiplier.
A 6.0:12 pitch means 6.00″ of rise for every 12″ of horizontal run. Multiply your flat footprint area by 1.118 to get the actual sloped roof area. Minimum pitch for standard shingles is typically 4:12 - below that, use modified bitumen or low-slope products.
Common Questions
What is a 6/12 roof pitch?
A 6/12 pitch means the roof rises 6 inches for every 12 inches of horizontal run. It is a moderate slope that handles rain well and is safe to walk on with proper footwear.
What is the minimum pitch for asphalt shingles?
Most asphalt shingle manufacturers require a minimum pitch of 4/12. Shallower roofs need low-slope or modified bitumen roofing products instead of standard shingles.
How does roof pitch affect the amount of material I need?
A steeper pitch means more actual roof surface than the flat footprint. A 12/12 pitch needs 41 percent more material than the footprint area. This calculator gives you the exact multiplier to use when ordering materials.
How do I measure roof pitch on an existing roof?
Place a level horizontally against the roof. Measure 12 inches along the level from the roof surface. Then measure straight down from that 12-inch mark to the roof. That number is your rise, and the pitch is rise/12.
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