Linear Feet to Board Feet Calculator
Board feet = thickness × width (in inches) × linear feet ÷ 12. Enter the board size, then type linear feet or board feet and the other fills in. Prices convert the same way. Free, no sign-up.
1 linear foot of 1 × 6 = 0.5 board feet.
Board feet = 1 × 6 × linear feet ÷ 12.
120 linear feet of 1 × 6 is 60 board feet.
The formulas
Board feet = T × W × linear feet ÷ 12
Linear feet = board feet × 12 ÷ (T × W)
T and W are the thickness and width in inches. A board foot is 144 cubic inches (NIST Handbook 130, §2.12.1.1), so one foot of length holds T × W ÷ 12 board feet. Both formulas are that definition rearranged; they're derived, not quoted.
Worked examples
- 120 linear feet of 1×6 trim: 1 × 6 × 120 ÷ 12 = 60 board feet.
- 100 board feet of 8/4 hardwood, 8″ wide: 100 × 12 ÷ (2 × 8) = 75 linear feet.
- 1×6 at $9.25 per board foot: $9.25 × 1 × 6 ÷ 12 = $4.63 per linear foot.
Which size to enter
Use the size the board is sold by. Softwood board measure uses the nominal size, including fractions of an inch, so a 2×4 is figured as 2 × 4 even though it's 1-1/2″ × 3-1/2″ dry (PS 20-25, §2.2). Rough hardwood uses its quarter thickness, 8/4 = 2″, and a hardwood board under 1″ thick counts as 1″ (NHLA rules, ¶16). Pick Hardwood or Softwood in the calculator to apply the right rule.
Surfaced hardwood in stock widths isn't sold by the board foot. Its quantity must be stated by linear measure (with the surfaced width and thickness), by count, or by surface measure (NIST Handbook 130, §2.12.3.1). A store may advertise it by nominal size, marked “nom”, if it shows the actual sizes or the table of minimum surfaced sizes (§2.12.3.2). Converting such boards to board feet is an estimate for comparing prices; use the size the price is based on.
Surface measure, the square feet used for hardwood, is the width in inches × the standard length in feet ÷ 12, rounded to the nearest whole square foot; it leaves out the thickness (NIST Handbook 130, §2.12.1.4). To convert square feet and board feet at a given thickness, use the board feet to square feet converter. Buying decking? The deck board calculator works out how many boards of each length to buy.
Board feet per linear foot, common sizes
| Nominal | Dry surfaced size | BF per linear foot | Linear feet per BF |
|---|---|---|---|
| 1×2 | 3/4″ × 1-1/2″ | 0.167 | 6 |
| 1×3 | 3/4″ × 2-1/2″ | 0.25 | 4 |
| 1×4 | 3/4″ × 3-1/2″ | 0.333 | 3 |
| 1×6 | 3/4″ × 5-1/2″ | 0.5 | 2 |
| 1×8 | 3/4″ × 7-1/4″ | 0.667 | 1.5 |
| 1×10 | 3/4″ × 9-1/4″ | 0.833 | 1.2 |
| 1×12 | 3/4″ × 11-1/4″ | 1 | 1 |
| 2×4 | 1-1/2″ × 3-1/2″ | 0.667 | 1.5 |
| 2×6 | 1-1/2″ × 5-1/2″ | 1 | 1 |
| 2×8 | 1-1/2″ × 7-1/4″ | 1.333 | 0.75 |
| 2×10 | 1-1/2″ × 9-1/4″ | 1.667 | 0.6 |
| 2×12 | 1-1/2″ × 11-1/4″ | 2 | 0.5 |
Board feet use the nominal size; dry sizes are from PS 20-25 Table 3, the same minimums as NIST Handbook 130 Table 2 for hardwood stock widths.
Rough hardwood, board feet per linear foot
| Thickness | 4″ wide | 6″ wide | 8″ wide | 10″ wide |
|---|---|---|---|---|
| 4/4 | 0.333 | 0.5 | 0.667 | 0.833 |
| 5/4 | 0.417 | 0.625 | 0.833 | 1.042 |
| 6/4 | 0.5 | 0.75 | 1 | 1.25 |
| 8/4 | 0.667 | 1 | 1.333 | 1.667 |
Buying for a project rather than by the foot? The board foot calculator turns a finished cut list into the rough lumber to buy, and the how-to page explains board feet in more detail.
Linear feet and board feet FAQ
How many board feet are in a linear foot?
It depends on the board: thickness × width (in inches) ÷ 12. A linear foot of 1×12 or 2×6 is 1 board foot, a 1×6 is 0.5 and a 2×4 is 0.667. That's the board-foot formula with the length in feet (UW–Madison FEM-042) and a length of 1 foot, so it's derived.
Is a linear foot the same as a board foot?
No. A linear foot is a length only; a board foot is a volume of 144 cubic inches (NIST Handbook 130, §2.12.1.1). They come out equal only when thickness × width is 12 square inches, as with a 1×12 or a 2×6.
Should I use the nominal size or the actual size?
Use the size the board is sold by. Softwood board measure uses the nominal size, so a 1×6 counts as 1 × 6 though it's 3/4 × 5-1/2 dry (PS 20-25). Rough hardwood uses its quarter thickness, and a hardwood board under 1 inch thick counts as 1 inch (NHLA ¶16). Surfaced hardwood in stock widths is sold by the linear foot, piece or square foot rather than by the board foot (NIST Handbook 130, §2.12.3.1), so a conversion is only for comparing prices.
How do I convert a price per linear foot to a price per board foot?
Divide by the board feet in one linear foot: $/BF = $/LF × 12 ÷ (thickness × width). A 1×6 at $3.00 per linear foot is $6.00 per board foot. That's derived from the board-foot formula, not quoted from a source.
Sources
- National Institute of Standards and Technology. Handbook 130, Uniform Laws and Regulations: IV-B Method of Sale of Commodities. 2026. Used: §2.12.1.1 Board Foot: the volume of a board 1 ft long, 1 ft wide and 1 in. thick, or its equivalent (144 in³ of wood); §2.12.1.4 surface measure; §2.12.3.1 S4S stock widths: quantity by linear measure (surfaced width and thickness stated), by count (length, surfaced width and thickness stated) or by surface measure in square feet (thickness stated); §2.12.3.2 nominal sizes allowed when marked “nominal” or “nom” and the actual sizes or Table 2 are prominently displayed; Table 2 minimum surfaced sizes for kiln-dried hardwood lumber.
- National Institute of Standards and Technology. Voluntary Product Standard PS 20-25, American Softwood Lumber Standard. PS 20-25, January 2025. Used: §2.2 board measure computed from nominal size; Table 3 dry dressed sizes.
- National Hardwood Lumber Association. Rules for the Measurement & Inspection of Hardwood & Cypress. Effective January 1, 2023. Used: ¶14 standard thicknesses for surfaced (S2S) lumber; ¶16 board measure: standard thicknesses under 1 in. (thin stock) count as 1 in., measured before surfacing.
- University of Wisconsin–Madison, Department of Forestry. What Is a Board Foot? (Forestry Facts, Publication No. 42, FEM-042). August 1989. A. Jeff Martin.