Calculate roof pitch, angle, rafter length, and materials needed for your roofing project
Enter your roof measurements
Vertical rise
Horizontal run
Typical: 1-1.5 feet
Pitch Ratio
0:0
Angle
0.0°
Sheathing (4x8 sheets)
OSB or plywood
Shingles
Roofing squares
Note: Add 10-15% waste factor for cuts and mistakes. Consider additional materials: underlayment, drip edge, ridge cap, ventilation, and flashing.
2:12 (Low Slope)
9.5°
3:12
14.0°
4:12 (Standard)
18.4°
5:12
22.6°
6:12
26.6°
7:12
30.3°
8:12 (Steep)
33.7°
9:12
36.9°
10:12
39.8°
12:12 (45°)
45.0°
Roof pitch is the steepness or slope of a roof, expressed as a ratio of vertical rise to horizontal run. For example, a 4:12 pitch means the roof rises 4 inches for every 12 inches of horizontal distance.
The most common roof pitch in residential construction is 4:12 to 6:12. A 4:12 pitch (18.4°) is considered standard, while 6:12 (26.6°) is popular for homes in areas with snow or heavy rain.
You can measure roof pitch using a level and tape measure. Place a 12-inch level horizontally against the roof, then measure vertically from the end of the level to the roof surface. This vertical measurement is your rise (in a rise:12 ratio).
A low slope roof has a pitch of 3:12 or less (less than 14°). A steep slope roof is typically 9:12 or greater (more than 37°). Minimum pitch for asphalt shingles is usually 2:12, while metal roofing can go as low as 1:12.
Steeper roofs require more materials (shingles, sheathing, underlayment) because they have more surface area than the building footprint. A 12:12 pitch roof needs about 40% more materials than a flat roof.
Rafter length is the diagonal measurement from the ridge (top) to the eave (bottom edge) of the roof. It is calculated using the Pythagorean theorem based on the rise and run, accounting for overhang.
Hip roofs typically require 10-15% more materials than gable roofs because they have more roof surface area and more complex framing. However, hip roofs are often more wind-resistant and structurally stable.
A roofing square is a unit of measurement equal to 100 square feet. Shingles and roofing materials are typically sold by the square. For example, a 2,000 sq ft roof would need 20 squares of shingles.
Typical roof overhang is 12-18 inches (1-1.5 feet) for eaves and 6-12 inches for rakes. Overhangs protect walls from water, provide shade, and improve aesthetics. Climate and building style affect ideal overhang size.
Yes, steeper roofs cost more to build and maintain due to increased materials, more complex framing, and higher labor costs (safety equipment, slower work pace). Roofs steeper than 6:12 may require additional safety measures.
"This calculator is a lifesaver for quick estimates. The material calculations are spot-on, and I love that it handles both gable and hip roofs. Use it on every job!"
Mike Torres
Roofing Contractor
"Extremely accurate for framing calculations. The rafter length feature saves me so much time, and the pitch visualization helps explain concepts to clients."
Jennifer Park
Home Builder
"Built my own shed roof using this calculator. The common pitch presets and clear explanations made it easy to understand. Highly recommend for DIYers!"
David Richardson
DIY Homeowner
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