Rafter Length Calculator - Building Width & Roof Pitch to Length

Calculate exact rafter lengths instantly from building width and roof pitch (ratio or angle). Get accurate measurements for construction projects, material ordering, and roof framing.

Rafter Length Calculator

Calculate the length of rafters based on the building width and roof pitch. Enter the required measurements below to get an accurate rafter length calculation.

Input Measurements

ft
:12

Results

Rafter Length

0 ft

Calculation Formula

The rafter length is calculated using the Pythagorean theorem: Rafter Length = √[(Width/2)² + (Pitch × Width/24)²], where Width is the building width and Pitch is the roof pitch ratio.

Roof Visualization

Enter valid measurements to see the roof visualization
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Documentation

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