How to calculate baseboard
Baseboard runs along the bottom of every wall and stops at each doorway. So the amount you need is the room's perimeter, minus the doorways, plus some extra for the cuts at each corner.
Perimeter = 2 × (length + width)
Baseboard = (perimeter − doorways) × (1 + waste %)
Pieces = baseboard ÷ piece length, rounded up
Example: a 14 × 12 ft bedroom has a 52 ft perimeter. Two 3 ft doorways take off 6 ft, leaving 46 ft. With 10% extra that's 50.6 linear feet, or 7 pieces of 8 ft baseboard (or 5 pieces of 12 ft).
Planning your cuts
- Use the longest pieces you can manage for long walls. Every joint along a wall is a seam that can show.
- Where you must join two pieces mid-wall, use a scarf joint (two 45° cuts overlapping) over a stud.
- Inside corners look best coped; outside corners are mitered at 45°.
- Buy the same profile and finish for the whole house at once so pieces match.
Baseboard, shoe and quarter round
Shoe molding and quarter round are small trims that sit at the bottom of the baseboard, covering the expansion gap left by floating floors. They follow the same path as baseboard, so the same linear footage applies. When installing new flooring, plan for both.
Frequently asked questions
How do I calculate baseboard for a room?
Add up the length of every wall (the room's perimeter), subtract the width of each doorway, and add about 10 percent for miter cuts and mistakes. That's the linear footage to buy.
How much extra baseboard should I buy?
About 10 percent is a good default. Rooms with many corners, bay windows or angled walls can use 15 percent or more, because every corner means a miter or cope cut with some offcut.
What length does baseboard come in?
Common stock lengths are 8, 12 and 16 feet. Longer pieces mean fewer joints along a wall, but they are harder to carry and fit in a car. Many stores also sell primed MDF baseboard in 8 foot lengths.
Do I subtract doorways?
Yes. Baseboard stops at the door casing on each side, so subtract the full opening width. A standard interior door opening is about 3 feet wide including casing.
Can I use this for quarter round or crown molding?
Yes for quarter round and shoe molding, which follow the same path as baseboard. Crown molding runs along the ceiling and doesn't skip doorways, so set doors to zero for crown.