How much baseboard do I need?
Measure the perimeter of the room, subtract the door openings, and add 10–15% for cuts. A 16 × 12 ft room has a 56 ft perimeter; two 3 ft doorways take it to 50 ft, and 12% waste gives 56 lf — four 16 ft sticks.
Buy in the longest stock that fits your walls and your vehicle. A 16 ft stick runs a 14 ft wall in one piece; three 8-footers would put two scarf joints in the same wall, and every joint is somewhere for a shadow line to appear.
Count corners separately from length, because they drive the waste rather than the total. A room with six inside corners and short runs between them can waste 20% even though the perimeter looks modest.
How the calculation works
Net run = 2 × (length + width) − total door width. Cased openings are deducted at their full width; the trim stops at the casing on both sides.
Sticks = net run with waste ÷ stock length, rounded up. Rounding up matters more with long stock: 56 linear feet needs four 16 ft sticks (64 ft) but five 12 ft sticks (60 ft), so the shorter stock can buy less total material while adding joints.
Waste on trim comes from cuts, not from area. Every cope, mitre and scarf produces an offcut, and offcuts under about 18 inches rarely find a home. Ten percent covers a plain rectangular room; 15% is realistic once there are bays, alcoves or more than four corners.
Scarf joints — the joint in the middle of a long wall — are cut at 45 degrees so one piece overlaps the other, and they land on a stud so both halves have something to fasten to. A square butt joint opens into a visible dark line as soon as the wood moves.
Typical baseboard cost, mid-2026
| Material | Unit | Typical range |
|---|---|---|
| MDF primed baseboard | per lf | $1.20 – $3.00 |
| Primed finger-joint pine | per lf | $1.80 – $4.00 |
| Solid pine / poplar | per lf | $2.50 – $6.00 |
| Oak or hardwood | per lf | $4.00 – $12.00 |
| Quarter round / shoe | per lf | $0.80 – $2.50 |
| Installation labour | per lf | $2.00 – $6.00 |
| Caulk and filler | per room | $15.00 – $40.00 |
MDF is cheaper, straighter and paints beautifully, but it swells permanently if it gets wet. Do not use it in a bathroom, a laundry, or anywhere a floor gets mopped hard.
What goes wrong on this job
- Cope inside corners, mitre outside ones. A coped joint stays closed when the house moves through the seasons; a mitred inside corner opens into a visible wedge and no amount of caulk holds it.
- Buy the longest stock your walls need and your vehicle takes. Every joint you avoid is a joint that cannot open up later.
- Cut scarf joints at 45 degrees and land them on a stud. A square butt joint telegraphs as a dark line the first winter.
- Paint or prime the back edge as well as the front on MDF. It is the unsealed back that drinks moisture out of a wall and swells.
- Leave the trim in the room for a couple of days before fitting, especially solid wood. It moves with humidity, and trim fitted straight off a cold truck shrinks away from the corners.
Frequently asked questions
How do I calculate how much baseboard I need?
Add up the room perimeter, subtract the width of every door opening, then add 10–15% for cuts. Divide by your stock length and round up.
How much baseboard for a 12x12 room?
A 48 ft perimeter less two 3 ft doorways is 42 linear feet. With 12% waste that is 47 lf — three 16 ft sticks.
Should inside corners be coped or mitred?
Coped. A mitred inside corner opens as the framing moves seasonally, and the gap sits on the most visible line in the room. A cope closes on itself and absorbs that movement.
How much waste should I allow for trim?
10% for a simple rectangular room, 15% or more once there are bays, alcoves or more than four corners. Offcuts shorter than about 18 inches are rarely usable.