FullCalculator

Crown Molding Calculator

By Room Perimeter

Enter room perimeter directly

By Room Dimensions

Enter room length and width

Formula

Linear Feet = Perimeter x 1.10 | Pieces = Linear Feet / Piece Length

Frequently Asked Questions

How do I calculate crown molding needed?
Measure the room perimeter (or 2 x length + 2 x width) and add 10% for waste from miter cuts at corners. Divide by the molding piece length to get the number of pieces needed.
How much waste should I allow for crown molding?
Allow at least 10% waste for miter cuts at inside and outside corners. If you are new to installing crown molding, buy 1-2 extra pieces for practice cuts and mistakes.
What size crown molding should I use?
For standard 8-foot ceilings, use 3.5-5.5 inch crown molding. For 9-10 foot ceilings, use 5-7 inch molding. For ceilings above 10 feet, 7+ inches looks proportional.

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