Baseboard & Trim Calculator
Find how many pieces of baseboard, quarter round or crown molding to buy for a room.
How to use this trim calculator
Enter the room's length and width in feet. For baseboard and quarter round, count the doorways, since there's no trim across the floor there. Crown molding runs all the way around the ceiling, so doorways don't count. Choose the length of the pieces your store sells; longer pieces mean fewer joints on long walls.
For an L-shaped or open-plan room, measure each wall where trim will go and add them up, then enter the total as the length with a width of 0.
The math behind it
Linear feet = 2 × (length + width) − doorways × doorway width. Add 10% for miter cuts and mistakes (15% for crown, which is trickier to cut). Pieces = linear feet with extra ÷ piece length, rounded up.
Example: a 14 × 12 ft room with one 3 ft doorway needs 49 linear feet of baseboard. With 10% extra that's 53.9 ft, or 4 pieces of 16 ft trim.
Also on the shopping list
- Finish nails: 2 nails into each stud, about every 16 inches.
- Caulk and wood filler for the top edge, corners and nail holes. One tube of caulk covers a typical room.
- A coping saw for inside corners, which fit much better than two 45° cuts.
Often used together
Quick answers
How many feet of baseboard do I need for a 12 × 12 room?
The room has 48 ft of wall. Subtract about 3 ft for a doorway and add 10% for cuts, and you need about 50 ft: five 12 ft pieces or four 16 ft pieces.
Should crown molding be the same amount as baseboard?
Usually a bit more, since crown goes over doorways and cutting its compound angles wastes more material. Allow about 15% extra.
Do I need quarter round as well as baseboard?
Only if there's a gap between the floor and the baseboard, which is common with floating floors. It runs the same length as the baseboard.