Rafter Calculator — Roof Pitch, Length & Truss Estimator
CalcAiHub's Rafter Calculator is a powerful, precise online tool for framing and roofing projects. Easily compute rafter length, roof pitch, slope, and cut angles by entering your rise, run, or span dimensions.
Total width of the roof (wall to wall)
Vertical height from eaves to peak
🏗️ Rafter Calculator
Design your roof with precision. This calculator computes rafter lengths, roof pitch ratios, angles, and total roof area — essential data for construction planning, material ordering, and structural design.
💡 Why Use It
Accurate rafter calculations prevent costly mistakes and material waste. Knowing exact rafter lengths ensures proper framing, appropriate pitch angle handles water drainage efficiently, and roof area estimates help calculate material needs for shingles, underlayment, and insulation.
📊 What You Get
Rafter length from eaves to peak, roof pitch ratio (rise:run), roof angle in degrees, total roof area (both sides), roof perimeter, and comparison with industry standard pitch ratios for climate-appropriate design.
🚀 Get Started
Enter your roof span (width wall-to-wall) and roof rise (vertical height from eaves to peak) in your preferred unit, then click Calculate Rafter to get complete roof specifications for construction and material planning.