Compound Miter Calculator

Inputs

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Use crown mode when the molding lies flat on the saw table and the saw needs both miter and bevel settings.
Inside and outside corners use the same angle magnitudes; saw side, board face and left/right setup change.
Included angle between the two finished walls or trim runs. A square corner is 90 degrees.
°
Angle from the wall to the crown profile when installed. Common 38/52 crown uses 38 degrees here.
°
Approximate profile face width used only for wall/ceiling projection and the SVG preview.
in

Results

Default result
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Saw miter setting(M)
31.62°
Pass

crown on flat

Also computed

Saw bevel setting(B)Pass33.86°

tilt saw blade

Flat trim miter(M_flat)45°

Approx wall/drop projection(W_wall)2.758in

Approx ceiling projection(W_ceil)2.155in

Spring angle used(S)38°

Spring complement(90-S)52°

Top-view corner miter 31.6 deg corner 90.0 deg Profile on saw bevel 33.9 deg 38.0 deg spring
Method notes 4 notes
  • Crown mode assumes the crown is cut lying flat on the saw table, with spring angle measured from the wall.
  • Formula: miter = atan(sin(S) / tan(C/2)); bevel = asin(cos(S) x cos(C/2)).
  • Angles are magnitudes for a inside corner. Left/right and face-up/face-down orientation varies by saw, blade tilt and which piece you are cutting.
  • Real crown profiles, out-of-plumb walls, scarf joints and coping strategy can require shop adjustment after the calculated setting.

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