Compound Miter Calculator

Saw settings for tapered boxes, planters, hoppers, and splayed frames.

Number of sides

Side slope angle (°)

0° = straight-sided box. 90° = flat frame.

Miter angle

–

Swing the saw table/arm from 0° (square crosscut).

Saw from above

Blade bevel (tilt)

–

Tilt the blade from 0° (straight up).

Saw from the front

Dihedral angle

–

The inside angle between two neighboring sides, measured square to the corner where they meet. Set a bevel gauge to this to check a joint or rip a corner post.

Looking straight down the corner

Corner line slope

–

How steep the corner runs, from horizontal. It's always shallower than the sides. On a roof this is the hip rafter pitch.

Corner line vs. side slope, from horizontal

Other saw scales

Table saw miter gauge (if it reads 90° at square)	–
Table saw blade (if it reads 90° at vertical)	–
Angle each corner closes (top view)	–
Side slope from horizontal	–

Top view

Side profile

Cut both ends of every piece at the same settings, flipping or rotating the board between cuts as your saw requires. Always make a test cut in scrap first.

Framing a hip roof or gazebo?

The members-only Hip Roof Calculator gives hip and jack rafter lengths, cheek cuts, backing and drop, plus live roof diagrams.

Unlock the roof calculator