Compound Miter Calculator for Woodworking
Enter your corner angle and spring angle to get precise miter gauge and blade tilt settings for crown molding, picture frames, and angled joinery.
Miter Angle
31.6°
Set your miter gauge to 31.6°
Blade Tilt
33.9°
Tilt your blade to 33.9°
Complementary Miter
58.4°
If your saw reads from the fence
Complementary Tilt
56.1°
If your saw tilts the other way
Cut Diagram
What is a compound miter angle?
A compound miter involves two simultaneous angle cuts: the miter angle (across the face of the board) and the blade tilt or bevel (through the thickness). You need both when joining pieces that meet at a corner AND are tilted — like crown molding, picture frames with sloped profiles, or any angled joinery where the pieces aren't flat.
How to use these settings
- Measure your corner angle (90° for standard walls).
- Measure or look up the spring angle of your material — the angle between the back of the workpiece and vertical. For crown molding it's printed on the packaging (52/38 crown = 38° spring).
- Enter both values above and press Calculate.
- Set your miter saw gauge to the Miter Angle value.
- Tilt your blade to the Blade Tilt value.
- If your saw reads differently, use the complementary angles.
Common mistakes
- Entering the wrong number from a "52/38" label. The spring angle is the one measured from the wall — enter 38 for 52/38 crown, not 52. Sanity check: at a 90° corner, 38° spring should give miter 31.6° and bevel 33.9°, the crown detents on most saws.
- Forgetting inside vs. outside corners. Check the "Outside corner" box for outside corners — the cut direction reverses.
- Not testing on scrap wood first. Always make a test cut on scrap before cutting your actual material.
Frequently asked questions
- What is a compound miter angle?
- A compound miter combines two angle cuts: the miter (across the face of the board) and the bevel or blade tilt (through the thickness). You need both when joining pieces that meet at a corner and are tilted, like crown molding or sloped picture frames.
- What angles do I need for crown molding at a 90° corner?
- For 52/38 crown (the most common), cut flat on the saw: set your miter to 31.6° and bevel to 33.9° — the factory crown detents on most compound miter saws. For 45/45 crown: miter 35.3°, bevel 30°. See the crown molding angle chart for a quick reference.
- What is a complementary angle?
- Some miter saws read the angle from the fence (not the blade). If yours does, use the complementary angle: 90° minus the calculated value. This calculator shows both so you can use whichever matches your saw.
- How do I cut an outside corner?
- Check the "Outside corner" box. The miter and bevel values stay the same magnitude, but the cut direction reverses. The long point of the cut moves to the front (visible side) of the workpiece instead of the back.