How to calculate crown molding
Crown follows the whole perimeter of the room — and unlike baseboard, it never stops for a doorway:
Linear feet = perimeter × (1 + waste %)
Perimeter is 2 × (length + width). Add your waste allowance for mitered and coped corners, then divide by your piece length and round up to whole pieces. Because crown passes above doors and windows, there are no openings to subtract.
Common molding lengths
| Piece length | Good for |
|---|---|
| 8 ft | Easy to handle; most rooms |
| 12 ft | Fewer seams on long walls |
| 16 ft | Long, unbroken runs |
Crown molding materials
- MDF. Smooth, pre-primed, and affordable for painting — but heavy and easily dented, and it can't get wet.
- Polyurethane / foam. Lightweight and moisture-proof; many profiles install with adhesive and pre-formed corner blocks, which sidesteps tricky compound miters.
- Solid wood (pine, poplar, oak). For a stained, natural look or larger profiles; costs more and demands precise cuts.
- PVC. Waterproof crown for bathrooms, porches, and exteriors.
Sizing crown to your ceiling
As a rough guide, taller ceilings carry taller crown: roughly 2½–4 in for 8 ft ceilings, 4–6 in for 9 ft, and 6 in or more for 10 ft and up. Oversized crown in a low room feels heavy, while skinny crown in a tall room disappears.
Tips for cleaner corners
- Cope inside corners. Coping one piece over a square-cut mate hides gaps better than a compound miter — and handles out-of-square walls.
- Use a crown jig or chart. Compound miters are easy to cut backwards; mark your spring angle and test on scrap first.
- Scarf the long runs. Join pieces mid-wall with a 45° scarf joint so the seam nearly disappears.
- Prime and paint first. Finishing before installing means only the nail holes and seams need touch-up.
How much does crown molding cost?
Crown runs about $8–$30 per piece (roughly $1–$4 per linear foot) — foam and MDF at the low end, solid hardwood and wide profiles higher. Because the cuts are tricky, pro installation often costs more per foot than baseboard.
How to cut crown molding
Crown is the trickiest trim to cut because it sits at an angle between wall and ceiling. There are two methods:
- Nested (upside-down and backwards). Stand the molding against the saw fence the way it tilts on the wall — but flipped, with the ceiling edge down on the saw table. Then a simple 45° miter cuts the corner. It's fast once the orientation clicks, which is the part that trips people up.
- Laid flat with compound angles. Lay the molding flat and set both the miter and the bevel to the compound angles for your spring angle. More setup, but it handles wide crown that won't fit nested.
Either way, cope the inside corners for a tight fit, and consider pre-formed corner blocks on foam crown to skip the angle math entirely.