How Much Crown Molding Do I Need? Feet, Pieces and Corners
Crown molding goes along the top of every wall, so the amount you need is the distance around the room. A 14 × 12 ft room has 52 ft of wall, and with 10% extra for the corner cuts it needs 5 pieces of 12 ft. The crown molding calculator does it for your room.
Crown molding by room size
With 10% extra:
| Room | Feet around | Pieces of 12 ft | Pieces of 16 ft |
|---|---|---|---|
| 10 × 10 ft | 40 ft | 4 | 3 |
| 12 × 12 ft | 48 ft | 5 | 4 |
| 12 × 14 ft | 52 ft | 5 | 4 |
| 14 × 16 ft | 60 ft | 6 | 5 |
| 16 × 20 ft | 72 ft | 7 | 5 |
| 20 × 25 ft | 90 ft | 9 | 7 |
How much extra to buy
For a 14 × 12 ft room in 12 ft pieces:
| Extra | Pieces of 12 ft |
|---|---|
| 5% | 5 |
| 10% | 5 |
| 15% | 5 |
Cutting the corners
- Inside corners. Cope one piece to fit over the profile of the other. A coped joint stays tight, and a plain mitered one opens as the wood moves.
- Outside corners. Miter both pieces at 45 degrees, on a square corner.
- Along a wall. Join two pieces with a scarf joint (two matching angle cuts), over a stud, with glue.
- Upside down. Cut the molding with the face down and the top against the fence of the saw, so that it sits as it does on the wall.
Before you start
- Measure each wall, since a room is rarely square, and add the lengths.
- Find the studs along the top of the wall, and mark them, since you nail into them and into the top plate.
- Paint or stain the molding first, and fill the nail holes and the joints afterwards.
- Start with the longest wall that has no door, and work around the room.
- Use a test piece to set the saw before you cut the good molding.
See also the baseboard trim calculator for the other end of the wall, and the paint calculator for the walls. These are estimates: measure your own room.
Frequently asked questions
How much crown molding do I need for a room?
The distance around the room plus about 10%: a 14 by 12 ft room has 52 ft of wall and needs 5 pieces of 12 ft.
How many linear feet of crown molding is that?
Twice the length plus twice the width: 52 ft for 14 by 12 ft. Subtract any wall you leave bare.
How much waste should I allow?
About 10%. For 14 by 12 ft that is 5 pieces, and with 5% it is 5.
Do I cope or miter the corners?
Cope the inside corners (4 in a rectangular room) and miter the outside ones. A coped joint stays tight when the wood moves with the seasons.
What length of crown molding should I buy?
Long pieces mean fewer joints: 12 ft is common and 16 ft suits long walls, if you can carry them into the room.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.