How do I calculate linear feet?
A linear foot is 12 inches of length, whatever the width or thickness of the material. To get linear feet, measure each straight run and add them up. Convert inches to feet by dividing by 12, so 14 ft 6 in is 14.5 ft.
Linear feet = run 1 + run 2 + run 3 … (each in feet)
A 12 × 12 ft bedroom is 48 ft around. Add 10% for cuts and you need 52.8 ft, or four 16 ft pieces of baseboard. Subtract door openings before adding waste if you want a tighter count.
Square feet to linear feet
To cover an area with boards, divide the square feet by the board's width in feet. Use the actual width, not the nominal size: a 1 × 6 is 5.5 inches wide.
Linear feet = square feet × 12 ÷ board width (in)
200 sq ft of 5.5 inch boards: 200 × 12 ÷ 5.5 = 436.4 linear feet. Deck boards are usually gapped, about 1/8 inch, which brings it to 426.7 ft. With 10% waste that's 469.3 ft, or 30 boards 16 ft long.
| Board (nominal) | Actual width | Linear feet per 100 sq ft |
|---|---|---|
| 1 × 4 | 3.5 in | 342.9 |
| 1 × 6 or 5/4 × 6 | 5.5 in | 218.2 |
| 1 × 8 | 7.25 in | 165.5 |
| 1 × 10 | 9.25 in | 129.7 |
| 1 × 12 | 11.25 in | 106.7 |
These are tight-fit figures with no gap or waste. Tongue-and-groove boards lose some width to the tongue, so use their exposed face width.
Linear feet vs square feet vs board feet
Linear feet measure length only. Square feet measure area, length × width. Board feet measure volume of lumber: 1 board foot is 12 × 12 × 1 inch. Trim, fencing and decking are often priced by the linear foot, flooring by the square foot, and hardwood lumber by the board foot. For hardwood, use the board foot calculator.
Baseboard and trim
Measure each wall at the floor and add a run for each one. Leave out door openings. Baseboard and casing are commonly sold in 8, 12 and 16 ft lengths. Longer pieces mean fewer joints on long walls, so pick a length close to your longest wall. Allow about 10% for miters, or 15% for rooms with many corners.
Fencing and decking
Fence is priced by the linear foot of fence line. Measure each straight run and the total is your fence length. For posts, rails and pickets, use the fence calculator. For a whole deck, including joists and fasteners, use the deck calculator.
Pricing by the linear foot
Trim carpenters and fence installers often quote per linear foot. Enter your material price per foot or per piece, then switch to contractor mode to add markup and labor. The install rate sets your hours: a carpenter might run 20–30 ft of baseboard an hour but far less crown. Send the result on an estimate.
Questions
How many linear feet are in a square foot?
It depends on the width of the material. For 12 inch wide boards, 1 sq ft is 1 linear foot. For 6 inch boards it's 2, and for 5.5 inch boards about 2.18.
Is a linear foot the same as a foot?
Yes. A linear foot is 12 inches of length. The word linear just means width and thickness don't count.
How do I convert inches to linear feet?
Divide inches by 12. For example, 90 inches is 7.5 linear feet.
How much extra trim should I buy?
Typically about 10% for miters and cuts, and 15% for rooms with many corners or crown molding.