How to calculate linear feet
For pieces you can count, such as boards, trim or fence rails:
- Measure each piece in feet. Convert inches by dividing by 12: 6 inches is 0.5 ft.
- Multiply the length by the number of pieces of that length.
- Add the totals for each length together.
Worked example. 12 pieces of trim, each 8 ft 6 in long: 12 × 8.5 = 102 linear feet. At $2.50 per linear foot that costs $255.
For a run along a wall or fence line, measure the distance in feet. That distance is the linear footage.
Square feet to linear feet
Flooring, decking, siding and paneling are sold by the linear foot but cover an area. Divide the area by the width of each board in feet:
Linear feet = square feet ÷ (board width in inches ÷ 12)
Worked example. Covering 200 ft² with 1 × 6 boards (5 1/2 inches wide): 200 ÷ 0.458 = 436 linear feet. Add 10 percent for cuts and you need 480 linear feet, or 40 boards 12 ft long.
| Board | Actual width | Linear feet per 100 ft² |
|---|---|---|
| 1 × 4 | 3.5 in | 343 |
| 1 × 6 | 5.5 in | 218 |
| 1 × 8 | 7.25 in | 166 |
| 1 × 10 | 9.25 in | 130 |
| 1 × 12 | 11.25 in | 107 |
Widths are the dry dressed sizes in the American Softwood Lumber Standard. Planning a batten wall? The board and batten calculator spaces the battens and totals the linear feet for you.
Linear feet, square feet and board feet
| Unit | Measures | Used for |
|---|---|---|
| Linear foot | Length only | Trim, lumber, fencing, gutters, countertop edges |
| Square foot | Length × width | Floors, walls, roofs, sod |
| Board foot | 12 × 12 × 1 in of wood | Hardwood and rough lumber |
| Piece count | Number of units | Concrete blocks, pavers, sheets of plywood |
Questions about linear feet
What is a linear foot?
A linear foot (or lineal foot) is simply 12 inches of length, measured along the piece. Width and thickness don't count, which is why lumber, trim and fencing are priced this way.
How do I convert square feet to linear feet?
Divide the square feet by the width of the board in feet. For 5 1/2 inch boards, 100 ft² ÷ (5.5 ÷ 12) = 218 linear feet.
Is a linear foot the same as a foot?
Yes. "Linear" just makes clear you are measuring length, not area (square feet) or volume (board feet or cubic feet).
How many linear feet are in a 2 × 4 × 8?
Eight. The 2 × 4 describes the cross-section; the 8 is its length in feet.
Sources
- Actual widths of 1-inch nominal boards (1 × 4 is 3 1/2 in, 1 × 6 is 5 1/2 in, and so on): NIST, PS 20-20 American Softwood Lumber Standard, Table 3
Last reviewed November 9, 2026. Found a wrong figure? Tell us.