Miter Angle Calculator 📐

How to Use the Miter Angle Calculator

Select your cut type (flat trim for baseboards or crown molding for 3D compound cuts), choose whether you're cutting an inside or outside corner, and enter the corner angle measured with a protractor or angle finder. For crown molding, also enter the spring angle (the angle between the molding back and the wall, typically 38° or 45°). The calculator will instantly provide the miter and bevel angles to set on your miter saw.

Understanding Miter and Bevel Angles

Miter angle is the angle you set on the miter saw's base (horizontal rotation), while bevel angle is the tilt of the blade itself (vertical tilt). For simple flat trim cuts, only the miter angle is needed. For crown molding and other compound cuts, you need to adjust both the miter and bevel angles to achieve a tight-fitting joint.

Common Corner Angles and Applications

Professional Cutting Tips

• Measure twice, cut once: Use a reliable angle finder or protractor to measure the actual corner angle before cutting.
• Test cuts first: Always make test cuts on scrap pieces to verify your saw settings before cutting expensive trim.
• Mark your pieces: Clearly label each piece with its position (left/right, top/bottom) to avoid confusion during installation.
• Account for blade kerf: The saw blade removes material (kerf width), which can affect very precise joints.
• Consider wall irregularities: Walls may not be perfectly flat or plumb, requiring minor adjustments even with perfect angles.

Crown Molding Spring Angles

Crown molding "spring angle" refers to the angle at which the molding sits against the wall. The most common spring angles are:

• 38° spring angle (52/38 crown): The molding touches the wall at 52° and the ceiling at 38°. This is one of the most popular profiles.
• 45° spring angle (45/45 crown): Equal angles to both wall and ceiling at 45°. Common in traditional molding profiles.
• Custom angles: Some decorative moldings have unique spring angles that should be measured or obtained from manufacturer specifications.

Cutting Methods for Crown Molding

1. Nested (upside down and backwards): Place the molding upside down on the saw with the ceiling edge on the saw base. This requires only miter angle adjustments, no bevel.
2. Flat on the saw bed (compound cut): Lay the molding flat and adjust both miter and bevel angles. This method is what our calculator provides angles for, as it's more versatile for complex corners.

Troubleshooting Joint Gaps

If your miter joints have gaps after cutting at the calculated angles:

• Verify that you measured the actual corner angle correctly (walls may not be truly 90°)
• Check that your saw is properly calibrated with accurate angle scales
• Ensure the molding is held firmly against the fence during cutting
• Consider that walls may bow or have irregularities requiring fitting adjustments
• For crown molding, double-check that you used the correct spring angle for your specific profile