What Is a Compound Miter Angle Calculator?
Crown molding sits at a tilt against the wall and ceiling, so joining two pieces cleanly at a corner takes two simultaneous angles: a miter angle (how far you rotate the saw table) and a bevel angle (how far you tilt the blade). This calculator applies the standard trigonometric compound-angle formulas to give you both settings, for molding cut flat on the saw table — the method most trim carpenters use with a standard miter saw.
It replaces the printed crown molding angle charts carpenters have used for decades, letting you compute the exact numbers for your corner and spring angle instead of rounding to the nearest chart entry.
How to Read Your Results
Miter Angle (Saw Table)
The angle to rotate your miter saw's table to, measured from square, for this cut.
Bevel Angle (Blade Tilt)
The angle to tilt the saw blade to, combined with the miter angle above, for a true compound cut.
Corner & Spring Angle Used
These echo back your inputs so you can confirm you entered the right corner geometry and molding spring angle before cutting.
Real-World Example
A standard square (90°) inside corner is being trimmed with crown molding that has a 38° spring angle, the most common spring angle for stock crown molding.
| Item | Value |
|---|---|
| Corner angle | 90° |
| Spring angle | 38° |
| Miter angle | ≈31.6° |
| Bevel angle | ≈33.9° |
Instead of a plain 45° miter, the carpenter sets the saw table to about 31.6° and tilts the blade to about 33.9° — the classic non-round numbers that make crown molding notoriously tricky without a chart or calculator.
Tips for Cutting Crown Molding
- Always test-cut scrap first — small errors in corner squareness or spring angle measurement change both results.
- Confirm your molding's true spring angle by holding a piece against a framing square; not all "crown" profiles use 38° or 45°.
- Cutting flat (nested) needs both miter and bevel set together — some carpenters instead stand the molding vertically against a fence, which uses different angle math not covered here.
- Out-of-square corners are common in real houses; measure the actual angle rather than assuming 90°.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team