How to use the linear feet calculator
- Enter how many pieces you have or need, and the length of each in feet plus inches.
- Optional, board feet: enter the nominal thickness and width (a 2×6 is 2 and 6) to convert linear feet into board feet, the volume unit hardwood and some lumber yards price by.
- Optional, covering an area: enter the square feet and the width each board actually covers to find how many linear feet of decking, siding, flooring or shiplap you need.
Linear feet formulas
Linear feet = number of pieces × length of each (ft)
Inches to feet: inches ÷ 12 · feet to meters: × 0.3048
Board feet = linear feet × thickness (in) × width (in) ÷ 12
Linear feet to cover an area = square feet × 12 ÷ board face width (in)
One foot is defined as exactly 0.3048 meters (NIST). A board foot is 144 cubic inches, the volume of a board 1 inch thick, 12 inches wide and 1 foot long, and it is calculated from nominal sizes.
Linear feet vs. square feet vs. board feet
- Linear feet measure length only. Trim, baseboard, fencing, gutters and most dimensional lumber are priced this way.
- Square feet measure area. Flooring, drywall and roofing are sold by area.
- Board feet measure volume of wood, used for hardwood and rough lumber, so a thick board costs more per linear foot than a thin one of the same species.
Worked examples
Pieces to linear feet. 12 boards at 8 ft 6 in: 8.5 × 12 = 102 linear feet (31.09 m, 34 yards). As 2×6 lumber that is 102 × 2 × 6 ÷ 12 = 102 board feet; as 1×4 it would be 34 board feet.
Area to linear feet. A 200 sq ft deck with boards that cover 5.5 inches each (5.5 in actual width, gaps ignored), plus 10% waste: 200 × 12 ÷ 5.5 = 436.4 ft, × 1.10 = 480 linear feet, or 30 boards of 16 ft.
Nominal vs. actual board size
Lumber is named by its rough-sawn size, not its finished size. Under the American Softwood Lumber Standard (PS 20), a dry 2×4 measures 1.5 × 3.5 inches, a 2×6 is 1.5 × 5.5 inches and a 1×6 is 0.75 × 5.5 inches. Use the nominal size for board feet but the actual face width (or the exposure the manufacturer lists for siding) when covering an area.
Square feet to linear feet quick table
Linear feet needed per 100 sq ft, before waste:
- 3.5 in face (1×4, 2×4): 343 ft
- 5.5 in face (1×6, 2×6, 5/4 decking): 218 ft
- 7.25 in face (1×8): 166 ft
- 9.25 in face (1×10): 130 ft
Tips
- Buy in stock lengths. Convert linear feet to pieces using lengths that suit your layout (8, 10, 12 or 16 ft) so joints land on framing.
- Add 10% waste for straight runs and 15% for diagonal patterns or many short pieces.
- Planning a feature wall? The board and batten calculator works out batten count and spacing directly.
Frequently asked questions
How do you calculate linear feet?
Measure the length of each piece in feet and add them together. With inches, divide inches by 12 first. Twelve pieces of 8 ft 6 in are 12 × 8.5 = 102 linear feet.
How do I convert square feet to linear feet?
Divide the square footage by the width of the material in feet, or multiply square feet by 12 and divide by the width in inches. 100 sq ft of 5.5 inch boards is 218 linear feet.
Is a linear foot the same as a foot?
Yes. A linear foot is just 12 inches of length, with no width or depth involved. The word "linear" separates it from square feet and cubic feet.
How many board feet are in a linear foot?
Board feet per linear foot = thickness × width ÷ 12 using nominal sizes. A 2×6 has 1 board foot per linear foot, a 2×4 has 0.67 and a 1×6 has 0.5.
How many linear feet are in a yard?
There are 3 linear feet in a linear yard and 3.28 linear feet in a meter.