Calculate linear feet from board lengths or floor area, convert square feet and board feet, and estimate project cost with an adjustable waste allowance.
Linear Feet Formula
Linear feet measure length only, so the formula depends on what you are solving for. The calculator covers five common cases.
Total linear feet from pieces:
LF = L * N * (1 + W/100)
Linear feet needed to cover a floor area:
LF = (A / Wd) * (1 + W/100)
Square footage covered by a run of linear feet:
SqFt = LF * Wd
Project cost from linear feet:
Cost = LF * (1 + W/100) * P
Linear feet to board feet:
BF = LF * (Wb * T) / 12
- LF = linear feet (length of material)
- L = length of one piece, converted to feet
- N = number of pieces or rows
- W = waste or overage allowance, in percent
- A = area to cover, converted to square feet
- Wd = board or plank width, converted to feet
- SqFt = square footage that the linear feet will cover
- P = price per linear foot
- BF = board feet (a volume measure)
- Wb = board width in inches
- T = board thickness in inches
The first mode multiplies the length of one piece by how many pieces you have, then adds your waste percentage. The area mode divides the area by the board width so wider boards need fewer linear feet. The coverage mode reverses that to tell you how much area a known length of board will cover. The cost mode applies your waste percentage to the linear feet and multiplies by the unit price. The board foot converter uses width and thickness because board feet measure volume, not length, so a thicker or wider board contains more board feet per linear foot.
Common Board Widths and Linear Feet per 100 Square Feet
Because linear feet needed depends on board width, narrower boards always require more length to cover the same area. The table below shows linear feet needed to cover 100 square feet at common widths, using the actual coverage width in feet.
| Board Width | Width in Feet | Linear Feet per 100 sq ft |
|---|---|---|
| 3 in | 0.25 | 400 |
| 4 in | 0.333 | 300 |
| 5 in | 0.417 | 240 |
| 6 in | 0.5 | 200 |
| 8 in | 0.667 | 150 |
| 12 in | 1.0 | 100 |
Add a waste allowance on top of these figures. Choose an allowance appropriate to the material, layout and supplier instructions; the calculator does not choose one.
Example Problems
Example 1. You are installing 6 inch wide flooring boards in a room that is 200 square feet, and you want a 10 percent waste allowance. The board width is 6 in, which is 0.5 ft. Linear feet equals 200 divided by 0.5, which is 400, then multiplied by 1.10 for waste. That gives 440 linear feet to buy.
Example 2. You have 25 deck boards, each 12 feet long, and want no waste. Linear feet equals 12 times 25, which is 300 linear feet. If those boards are 5.5 inches wide and 1 inch thick, the board feet equal 300 times 5.5 times 1 divided by 12, which is about 137.5 board feet.
Frequently Asked Questions
What is the difference between linear feet and square feet? Linear feet measure length in a straight line and ignore width. Square feet measure area, which is length times width. You convert between them using the board or material width: divide square feet by the width in feet to get linear feet, or multiply linear feet by the width in feet to get square feet.
How are linear feet different from board feet? Linear feet measure only the length of a board. Board feet measure volume and depend on length, width, and thickness. One board foot equals 144 cubic inches, which is a piece 12 inches by 12 inches by 1 inch. A long but thin and narrow board can have many linear feet but few board feet.
How much waste should I add? Choose an allowance for your material and cutting layout. Enter it under Optional settings for a length or cost estimate; it is applied when you select Calculate. Coverage and board-foot conversion do not apply an allowance.
