Compound Miter Calculator

Miter & bevel settings for crown molding and angled joints

Corner angle (°)

Spring angle from wall (°)

Miter Angle (saw)

31.6°

Bevel Angle (blade tilt)

33.9°

How to use this compound miter calculator

This assumes the “flat method” — molding laid flat on the saw table rather than tilted against a fence. Enter your corner angle (90° for a standard square corner) and the molding’s spring angle (the angle it sits at between the wall and ceiling — 38° and 45° are the two most common spring angles for stock crown molding, so those are included as quick presets).

Formula

K = 90° − Spring Angle
Miter Angle = arctan( cos(K) ÷ tan(Corner Angle ÷ 2) )
Bevel Angle = arcsin( sin(K) × sin(Corner Angle ÷ 2) )

For a 90° corner and 38° spring molding, this works out to a 31.6° miter and 33.9° bevel — matching the values on most published crown molding charts, which is a good way to sanity-check your saw against this tool the first time you use it.