About the Baseboard Calculator
This baseboard calculator estimates how much baseboard, shoe molding or quarter-round a room needs. Enter the room length and width, the number of doorways and their width, and it calculates the linear footage around the perimeter, subtracts the doorways where trim is not installed, adds a waste allowance for miters and coped joints, and tells you how many pieces to buy in the stock length you choose.
Use it when replacing trim, finishing a basement, or installing new flooring that needs fresh baseboard or shoe molding. For irregular rooms, add the length of every wall and enter the total as the length with a width of zero; for several rooms, run each room and add the piece counts.
Buying longer pieces reduces joints along long walls. A waste allowance of 10% suits simple rectangular rooms; allow 15% or more for rooms with many outside corners, bay windows or columns.
With the default inputs, the pieces to buy is 4. Change any value above to recalculate instantly.
How to use the baseboard calculator
- 1Measure the room length and width along the walls.
- 2Count doorways and enter their width (closet and cased openings too).
- 3Set a waste allowance: 10% for simple rooms, 15% for complex ones.
- 4Choose the stock length you will buy and enter the price per foot.
- 5Buy the pieces shown; use the longest pieces on the longest walls.
Formula and method
The perimeter of a rectangular room is twice the sum of its length and width. Baseboard is not installed across doorways, so each doorway width is subtracted. A waste percentage is then added for miter and cope cuts, joints and short offcuts that cannot be reused.
Dividing the total by the stock length and rounding up gives the number of pieces to buy. Cost uses the price per linear foot multiplied by the footage you actually purchase (pieces × piece length), because you pay for whole pieces.
- Length, Width
- Room dimensions (ft)
- Doors
- Number of doorways without baseboard
- Waste%
- Allowance for cuts and joints
Worked examples
12 × 14 ft bedroom with one door
The perimeter is 2 × (14 + 12) = 52 ft. Subtracting a 3 ft doorway leaves 49 ft, and 10% waste makes 53.9 ft. That needs four 16 ft pieces (64 ft), costing $96 at $1.50 per foot.
15 × 20 ft living room, two doors, 12 ft stock
The perimeter is 70 ft and two doorways remove 6 ft, leaving 64 ft. With 15% waste that is 73.6 ft, which needs seven 12 ft pieces (84 ft) at $2.25 per foot, or $189.
Frequently asked questions
How do I calculate linear feet of baseboard?+
Add up the length of every wall that gets baseboard, then subtract the width of doorways. For a rectangular room this is 2 × (length + width) minus the doorways.
How much extra baseboard should I buy?+
Add about 10% for simple rooms and 15% or more for rooms with many corners. Miter and coped joints, scarf joints on long walls and occasional miscuts all consume extra material.
What length does baseboard come in?+
Stock baseboard is commonly sold in 8, 12 and 16 ft lengths, with some profiles in 10 and 14 ft. Longer pieces mean fewer joints on long walls but are harder to transport.
Do I need baseboard inside closets?+
Usually yes — closets are trimmed like the rest of the room. Add the closet perimeter to your wall total and enter the closet doorway as another doorway.
Is shoe molding calculated the same way?+
Yes. Shoe molding or quarter-round runs along the bottom of the baseboard, so it needs the same linear footage. Run the calculator again with its price per foot.