Miter Angle Calculator

For a standard rectangular frame with 90° corners, each piece is cut at 45° (half of 90). For irregular frames, divide the corner angle by 2. For example, a 60° corner requires 30° miter cuts. Most miter saws have positive stops at common angles (22.5°, 30°, 45°), but you can set any angle for custom frames. Always cut test pieces on scrap wood first.

For a regular hexagon (6 sides), each interior angle is 120°, so each miter cut is 60° (half of 120°). Alternatively, use the formula 180/n where n is the number of sides: 180/6 = 30°. Wait — this depends on whether you cut the miter perpendicular or parallel to the face. For flat miters on a table saw: set blade to 30° for a 6-sided frame. For picture frames cut on a miter saw: set to 30° as well.

The spring angle is the angle between the back of the crown molding and the wall when installed. The two most common spring angles are 38° and 45°. Your crown molding should have the spring angle printed on it or in the product specs. Using the wrong spring angle results in gaps at the corners. The calculator handles both standard angles and custom spring angles for compound miter cuts.

Crown molding corners can be cut using either the compound method (miter and bevel) or the coping method. The compound method uses one miter saw setting for both pieces. The coping method (preferred for inside corners) makes a square cut on one piece and copes (profiles) the other to fit. For outside corners, always use compound miter cuts. The calculator provides the exact miter and bevel settings for your specific wall angle and spring angle.