Roofing
Rafter Length Calculator
Your measurements : vertical rise, horizontal run, horizontal overhang. Your estimate : length.
How the calculation works
Rafter Length Calculator
√(Vertical rise² + Horizontal run²) × (1 + Horizontal overhang / Horizontal run)Before you order
- A simple roof with one uniform pitch is assumed. Length and width are horizontal plan dimensions; overhang is horizontal on every side. Valleys, hips, dormers and overlaps need separate allowances.
- Planning estimate only. This is not a structural design, a safety approval or a local code check.
Worked example
- Vertical rise
- 2 m
- Horizontal run
- 4 m
- Horizontal overhang
- 0.3 m
Length 4.81 m