Crown Molding Cut Angle Calculator
Get the miter and bevel saw angles to cut crown molding flat on a compound saw for any wall corner and spring angle.
How it works
miter = atan( sin(spring) × tan(corner/2) ) · bevel = asin( cos(spring) × sin(corner/2) )
Crown molding meets the wall at a spring angle, so cutting it flat on a compound miter saw needs both a miter (table swing) and a bevel (blade tilt). The formulas take half the corner angle and the molding’s spring angle and return both saw settings. Alternatively you can cut it nested — held against the fence at its spring angle — with a plain 45° miter, but the flat, compound method is what these numbers are for.
Worked example
A standard square inside corner is 90°, so half is 45°. With 38° spring crown: miter = atan(sin38° × tan45°) = 31.6°, and bevel = asin(cos38° × sin45°) = 33.9° — the classic 31.6/33.9 pairing every compound-miter chart lists for 38° crown.
Frequently asked questions
What is the spring angle?
It is the angle between the back of the molding and the wall — 38° and 45° are the two common US profiles (often marked 52/38 for the two wall/ceiling contact angles). Read it off the molding’s end profile; it sets the bevel.
Cut flat or nested?
Nested (upside down against the fence) lets you use a simple 45° miter and is fast for square corners, but wide crown won’t fit the saw. Cutting flat on the table uses the compound miter/bevel here and handles any corner and any width.
How do I handle out-of-square corners?
Measure the actual corner with a protractor or bevel gauge and enter it — old houses are rarely a true 90°. Always test-cut scrap and dry-fit before cutting your finished stock, since a degree off shows as a gap.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.