Baseboard Calculator

Work out the linear feet and number of pieces of baseboard or trim you need for a room — with doorways and a waste allowance accounted for — plus the cost.

How to measure an area — length times width Length Width
Measure the area — length × width.

How to calculate baseboard

Baseboard follows the perimeter of the room, minus the openings:

Linear feet = (perimeter − doorways) × (1 + waste %)

Perimeter is 2 × (length + width). We subtract about 3 feet for each standard doorway, add your waste allowance for cuts and mitered corners, then divide by your trim length to get the number of pieces, rounded up.

Common trim lengths

Piece lengthGood for
8 ftEasy to handle; most rooms
12 ftFewer joints on long walls
16 ftLong, unbroken runs

Baseboard materials and styles

The material decides the price and whether you paint or stain it:

  • MDF. The cheapest, smoothest paint-grade option — comes pre-primed, but it swells if it gets wet.
  • Finger-joint pine. Solid wood made for painting, with glued joints hidden under primer.
  • Solid wood (pine, oak, poplar). For a stained, natural look or where durability matters; costs more.
  • PVC / polystyrene. Waterproof trim for bathrooms, basements, and exterior use.

Heights run from a modest 3¼ in up to 5¼ in or taller for a more substantial look — taller profiles suit higher ceilings.

Don't forget the finishing touches

  • Shoe molding or quarter-round covers the gap where the baseboard meets an uneven floor — add a second pass of the perimeter if you're using it.
  • Caulk and filler for the top edge and nail holes, plus paint or stain.
  • Going bigger up top? Pair it with crown molding — size that with our crown molding calculator.

How much does baseboard cost?

Trim runs about $6–$25 per piece (roughly $1–$3 per linear foot) — MDF and finger-joint pine at the low end, solid hardwood and tall profiles higher. Pro installation typically adds $1–$3 per linear foot.

Tips

  • Plan long walls first. Use full lengths on the longest walls to minimize visible seams.
  • Corners eat material. Mitered inside and outside corners create offcuts — keep the 10% buffer.
  • Buy matching shoe molding if your floors aren't perfectly flat.

How to install baseboard

  1. Start with the longest wall. Cut the first piece square end-to-end and set it tight into both corners.
  2. Cope inside corners. Leave one piece square in the corner and cope the mating piece — cut its profile so it nests over the first. Coped joints stay tight even when walls aren't square.
  3. Miter outside corners. Cut both pieces at 45° (or split the real angle) so they wrap the corner cleanly.
  4. Nail into the studs. Fasten near the top and bottom with a brad or finish nailer, hitting studs where you can.
  5. Fill and caulk. Fill nail holes, caulk the top edge and any corner gaps, then touch up the paint.

Frequently asked questions

How much baseboard for a 12x12 room?
The perimeter is 48 ft. After subtracting one doorway and adding 10% waste, you'll need about 50 linear feet — roughly 7 pieces of 8 ft trim.
How do I work out the number of pieces?
Divide your total linear feet (with waste) by the piece length and round up. Baseboard usually comes in 8, 12, or 16 ft lengths.
Should I subtract doorways?
Yes — about 3 ft per standard doorway, since openings get no baseboard.
How much extra should I buy?
About 10%, more for rooms with lots of corners and miters.
What's the best baseboard material?
MDF is cheapest and smoothest for painting; solid wood is best for staining or high durability; PVC is the choice for bathrooms and other damp spots.
What height of baseboard should I use?
3¼–4¼ in suits standard 8 ft ceilings; 5¼ in or taller looks proportionate with 9 ft or higher ceilings.
Do I need quarter-round or shoe molding?
It's optional but helps hide gaps over uneven floors and after new flooring. If you use it, buy another full perimeter's worth.
Should I cope or miter inside corners?
Cope them. A coped joint — where one piece is cut to fit the other's profile — stays tight even when walls aren't perfectly square, unlike a 45° miter that opens up over time. Miter the outside corners.
Do I install baseboard before or after flooring?
Usually after, so the trim covers the flooring's expansion gap. With carpet, install the baseboard first and tuck the carpet under it. Either way, add shoe molding last.

How we calculate this

  • Length = room perimeter minus door openings
  • A waste allowance is added for miter cuts and mistakes
  • The total is divided by the stock length and rounded up to whole pieces

Sources: Standard trim-carpentry practice. Last reviewed: June 2026. See our methodology for how we build every estimate.