Crown Molding Calculator

Divide the total linear feet including waste by the stick length and round up. A 14 × 12 room has a 52 ft perimeter, about 58 ft with 12% waste, which is five 12 ft sticks. Where you can, buy sticks longer than your longest wall so that wall runs unspliced — a visible scarf joint in the middle of a 14 ft wall is the most common giveaway of a DIY install. If you must splice, cut a 45-degree scarf so one piece overlaps the other, land it on a stud, glue it, and keep it out of the main sightline from the doorway.

Cope them. Inside corners in real houses are rarely a true 90 degrees, and a mitered inside corner opens into a visible crack the first season the framing moves. Coping — running one piece square into the corner, then back-cutting the second piece to the exact profile so it laps over the first — stays tight even at 88 or 92 degrees. Outside corners are mitered, and those you should always test-fit on scrap first. A rectangular room has four inside corners, and a hand-coped joint takes most people 10–15 minutes each until the technique clicks.

Spring angle is how far the molding leans off the wall. Most US crown is 38/52 (38 degrees to the wall, 52 to the ceiling); the other common profile is 45/45. It sets your saw settings. Cutting 38/52 crown lying flat on the saw table needs a compound setting of about 31.6 degrees miter and 33.9 degrees bevel for a 90-degree corner, while 45/45 crown needs 35.3 and 30. Cut it nested instead — upside down and backward against the fence at its spring angle — and a plain 45-degree miter works. Confirm your profile before you burn a full stick.

Ten to fifteen percent is the working range, and crown sits at the high end because every joint is a compound cut and one blown cope costs you the end of a stick. Use 10% in a simple rectangular room with long walls, 15% or more with many short walls, bays, or a first attempt at coping. This calculator defaults to 12%. Remember that waste is not evenly spread: a 3 ft offcut is useless on a 12 ft wall, which is exactly why the stick count — not the linear-foot total — is what you actually buy.

Yes. Prime and lay on one or two finish coats while the sticks are flat on sawhorses, then touch up after install. Painting overhead against a finished ceiling is slow and you will cut into the ceiling line. Once it is up, set the nails, fill the holes, caulk the top and bottom edges with paintable latex caulk, and brush a final coat. Bare MDF and finger-jointed pine need priming on all faces regardless — unsealed MDF swells if it picks up moisture, and raw end cuts soak up paint like a sponge unless you seal them first.