How the baseboard calculator works
Linear feet = 2 × (length + width) − doorways × 3
Pieces = linear feet × (1 + waste) ÷ piece length, rounded up
Example: a 12 × 12 ft bedroom with one door
The perimeter is 48 feet. Minus a 3 ft doorway leaves 45 feet, and with 10% extra for miters that's 49.5 feet. In 16 ft lengths, buy 4 pieces (64 feet), about $96 at $1.50 a foot.
Longer pieces mean fewer joints along a wall. The same calculation works for crown molding and shoe molding.
Frequently asked questions
How much extra baseboard should I buy?
About 10% for miter cuts and mistakes, more if the room has many corners or angled walls.
Should I subtract doorways?
Yes. Baseboard stops at the door casing, so subtract the width of each doorway, usually about 3 feet.
Last reviewed: 2026-10-31