Woodworking & Construction Calculators

Fine woodworking & cabinetry

Crown Molding Miter and Bevel Calculator

Spring is the angle between the wall and the back of the crown (38°, 45° or 52° are common). Wall angle is 90° for a square inside corner.

Inputs

Units
°

Results

Miter (table)
31.62°
Bevel (blade tilt)
33.86°

Recommended gear

Calculation method

A 52° spring on a 90° inside corner is about 31.6° miter and 33.9° bevel — the pair most US crown charts publish. Outside corners use the supplement of the wall angle so the same trig still applies.

Exact formula

miter = arctan(cos(spring) / tan(included/2)). bevel = arcsin(sin(spring) × sin(included/2)). Outside corners use included = 360° − wall.

Angles do not unit-convert

Degrees are the same in metric and imperial. Only a measured wall corner in millimetres vs inches on a protractor would change — this tool takes the corner in degrees either way.

Frequently asked questions

My 45° crown does not match 31.6° / 33.9°.

Those numbers are for 52° spring. 45° spring on 90° is about 35.3° miter and 30.0° bevel.

Do I flip the saw for left vs right?

Yes. The magnitudes stay; the miter direction and which face is against the fence change.

Should I cope inside corners?

Often. Cut one piece square and cope the profile; miter the outside corners.

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