Crown Molding Calculator
Calculate how much crown molding you need for a room.
Enter the room perimeter and number of corners to plan your purchase.
Crown Molding Needed
Crown molding is measured in linear feet or meters along the room perimeter.
Total Molding = Room Perimeter + Waste Allowance
Pieces Needed = Total Length / Piece Length (rounded up)
Measuring your room:
- Measure each wall where molding will be installed
- Subtract any open doorways or pass-throughs
- Add the measurements together for total perimeter
Standard molding lengths:
- US: Sold in 8 ft, 12 ft, or 16 ft pieces
- Metric: Sold in 2.4 m, 3 m, or 4 m pieces
Waste allowances:
- Rectangular room (4 inside corners): Add 5–10%
- Complex room (many corners): Add 10–15%
- First-time installer: Add 15–20% for learning cuts
Corner types:
- Inside corners (concave): Use coped joint or miter joint
- Outside corners (convex): Use miter joint
- Each corner wastes ~6–12 inches due to angled cuts
Cost guide (2025):
- MDF/Polystyrene: $1–3/linear foot
- Pine/Poplar: $2–5/linear foot
- Hardwood (oak, maple): $4–10/linear foot
- Professional installation: $3–8/linear foot labor