Baseboard and trim calculator
How many linear feet of baseboard or trim a room needs, and how many 8, 12 or 16 ft pieces to buy.
Baseboard
- Pieces to buy
How to use it
Enter the room's length and width in feet, the number of doorways, and their width. Choose the length of trim you'll buy. The calculator works out the linear feet of baseboard and the number of pieces, with 10% extra for miter cuts and waste.
The same calculation works for crown molding and chair rail, except that crown and chair rail usually run across doorways too: set doorways to 0 for those.
How it's calculated
- Perimeter = 2 × (length + width).
- Linear feet = perimeter − (doorways × doorway width ÷ 12).
- Pieces = linear feet × 1.1 ÷ piece length, rounded up.
| Room | 1 doorway (36 in) | 16 ft pieces with 10% extra |
|---|---|---|
| 10 × 10 ft | 37 linear ft | 3 |
| 12 × 14 ft | 49 linear ft | 4 |
| 15 × 20 ft | 67 linear ft | 5 |
Tips
- Buy the longest pieces you can carry. Fewer joints look better, and a 16 ft piece often covers a whole wall without a splice.
- Where pieces must join on a straight wall, use a scarf joint (two 45° cuts overlapping) over a stud, not a square butt joint.
- Inside corners look best coped rather than mitered; outside corners are mitered.
- Add for closets and any built-ins you're trimming around, which are easy to forget.