Hip & Valley Rafter Calculator

Hip or valley rafter length, jack rafter lengths, and every plumb and cheek cut — for regular or irregular (two-pitch) hip roofs. Free, no sign-up.

Enter the building width and the main roof pitch. For a regular hip, the end of the roof has the same pitch; choose irregular when the hipped end is steeper or flatter, and its overhang is set so the fascia stays level all the way round.

Lengths are along the top edge at the rafter's centreline, from the ridge (or the hip, for jacks) to the end of the tail, after taking off half the ridge and half the hip. Cheek cuts are the saw bevel, measured from square.

Jack rafters step down by the same amount each time. The hip's drop is how much to lower its seat (or back its top edges) so the sheathing lies flat across it.

Valleys between two roofs of these pitches use the same lengths and cuts. Valleys aren't dropped.

Taulien Construction · Fredericton, New Brunswick · info@taulien.com · 506-230-5131