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Baseboard Calculator: Linear Feet of Trim
Find out how many linear feet of baseboard or shoe molding a room needs after doorways, how many 8, 12 or 16 ft pieces to buy, and what it costs, with nails and caulk included.
How to calculate baseboard
Baseboard runs around the bottom of every wall except where a doorway or a built-in cabinet interrupts it. Measure the room's perimeter, take away the width of each doorway, and add waste for the miter and cope cuts at each corner:
baseboard (ft) = 2 × (length + width) + extra walls − doorways × door width, then add 10%
Example: a 12 × 14 ft room has a 52 ft perimeter. Taking away one 3 ft doorway leaves 49 ft. With 10% waste you need about 54 ft, which is four 16 ft pieces (64 ft) or five 12 ft pieces (60 ft). At $1.50 a foot, four 16 ft pieces cost $96.
Which piece length should you buy?
Longer pieces mean fewer joints on long walls, and joints are where baseboard looks worst. Buy pieces at least as long as your longest wall when you can, so each wall is one piece. If a wall is longer than your stock, join pieces with a scarf joint (two 45° cuts that overlap) over a stud, not a butt joint.
| Wall length | Best piece |
|---|---|
| Up to 7 ft | 8 ft |
| 7 to 11 ft | 12 ft |
| 11 to 15 ft | 16 ft |
| Over 15 ft | 16 ft with one scarf joint |
How much waste to add
- 5% for a simple rectangular room with long pieces.
- 10% for most rooms (our default), which covers a miscut or two.
- 15% for rooms with many short walls, bay windows, columns or angled corners.
Other trim in the same room
Crown molding uses the same perimeter but does not stop at doorways, so set doorways to 0. Shoe molding or quarter round, which hides the gap where the baseboard meets a hard floor, uses the same length as the baseboard. Door casing needs about 17 ft per side of a standard interior door (two legs and a head), so 34 ft for both sides.
Installing new floors too? Try our flooring calculator, and the paint calculator for the walls.
Frequently asked questions
How much baseboard do I need for a 12x12 room?
A 12 × 12 ft room has a 48 ft perimeter. Minus one 3 ft doorway that is 45 ft, or about 50 ft with 10% waste: five 12 ft pieces, or three 16 ft pieces plus one 8 ft piece.
Do you subtract doorways for baseboard?
Yes. Baseboard stops at door casings, so subtract the width of each doorway, usually about 3 ft including the casing. Do not subtract windows.
How much does it cost to install baseboard?
Material runs about $1 to $5 per linear foot for MDF or pine. Professional installation adds roughly $2 to $5 per foot, depending on the number of corners.