Rafter Line Length Calculator

Deduct half the thickness of the ridge from the span length this length
is the correct measurement from the top plumb line to the birdsmouth plumb line.

To get overall plumb to plumb length add overhang horizontal length to horizontal span
(less subfascia and fascia thickness)

Horizontal Span of Rafter(inches,run)
Roof Pitch (inches rise per foot of run)
Plumb to plumb line length (inches) =