Roofing & FramingConstruction

Roof Pitch, Slope Angle & Common Rafter Length Estimator

Calculate roof pitch factor (X/12), pitch angle in degrees (°), roof slope percentage (%), ridge rise height, and true rafter length including eaves overhang.

Calculated Result

Total Common Rafter Length (incl. Overhang)

4.92m

Calculator Inputs

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Total Common Rafter Length (incl. Overhang)

4.92m

Roof Slope Angle (°)

26.57 °

Ridge Peak Rise Height (m)

2 m

Roof Slope Percentage (%)

50 %

Horizontal Roof Run

4 m

Roof Run vs. Rise vs. Rafter Length Breakdown

Horizontal Roof Run
4 m(37%)
Vertical Rise Height
2 m(18%)
Final Cut Rafter Length
4.92 m(45%)

Structural rafter sizing (e.g., 2x6 vs 2x8) must comply with local snow loads and span tables.

All engineering calculations, structural estimates, and electrical sizing metrics are provided for preliminary estimation only. Always ensure compliance with relevant statutory building codes and occupational safety standards, verified by a certified professional engineer before practical implementation.

Calculation Methodology

Run = Building Width / 2. Rise = Run * (Pitch / 12). Rafter Length = Sqrt(Run² + Rise²) + Overhang Length.

Frequently Asked Questions

A 4:12 pitch means the roof rises 4 inches vertically for every 12 inches of horizontal run (approx. 18.4° slope); a 6:12 pitch rises 6 inches per foot (26.6° slope).

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