Calculate crown molding or coving length, number of pieces, inside and outside corners for any room.
Step 1: Enter the room length and width. For irregular rooms, measure each wall and enter the total as the length field.
Step 2: Enter the number of inside and outside corners in the room.
Step 3: Adjust waste percentage. 10% is standard; beginners may want 15–20% for cope cutting practice.
Results show how many pieces you need in standard lengths. Longer pieces mean fewer joints for a cleaner look.
Inside corners are typically cope-cut: one piece is butted into the corner, and the adjacent piece is cut to the profile shape using a coping saw. This accommodates walls that aren't perfectly square.
Longer pieces (12ft/3.6m) are preferred because they create fewer joints. However, they're harder to transport and handle. For rooms under 12ft wide, 12ft pieces can span entire walls.
Buy 10% extra for experienced installers, or 15–20% extra if you're a beginner. Crown molding cuts can be tricky, and the compound angles are easy to get wrong.