BOARD FOOT CALCULATOR
How it works
Ten pieces of nominal 2 × 6 lumber, each 12 feet long.
- Convert the length to inches: 12 ft × 12 = 144 in.
- Volume of one piece: 2 × 6 × 144 = 1,728 in³.
- Divide by 144: 1,728 ÷ 144 = 12 board feet per piece.
- Multiply by the count: 12 × 10 = 120 board feet.
120 board feet for the order — 12 board feet per piece.
Constants
| Constant | Value |
|---|---|
| One board foot | 144 in³ |
| Nominal vs actual 2×4 | 2" × 4" billed, 1.5" × 3.5" milled |
| Board feet in a 2×6×12 | 12 bd ft |
SOURCE — 1 board foot = 1 in × 12 in × 12 in = 144 in³, by definition. Nominal dimensions, as lumber is sold.
SOURCE — softwood dimensional lumber is sold at nominal size; the surfaced (S4S) dimensions are smaller after drying and planing. Yards price the nominal size.
SOURCE — (2 × 6 × 144) ÷ 144 = 12 board feet, using the nominal 2 in × 6 in section.
Quick answers
Ten 2×6 boards at 12 feet each are 120 board feet: 12 board feet per piece, using the nominal 2-inch by 6-inch section.
A board foot is 144 cubic inches — one inch thick, twelve inches wide, twelve inches long. The formula is thickness × width × length in inches, divided by 144.
Always use nominal dimensions. A 2×4 mills to 1.5" × 3.5", but the yard bills it as 2" × 4", so a quote from the milled size will not match the invoice.
A 2×4×8 is 5.33 board feet. At $3.50 per board foot that is $18.67 for the piece.
For hardwood sold in quarters, 4/4 means one inch thick and 8/4 means two inches — the numerator is the thickness in quarter-inches.
FAQ
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in inches, then divide by 144. If the length is in feet, multiply thickness × width × length in feet and divide by 12 instead — the same arithmetic.
How many board feet in a 2×4×8?
5.33 board feet. Two inches by four inches by 96 inches is 768 cubic inches, and 768 ÷ 144 = 5.33.
Do I use nominal or actual dimensions?
Nominal. A 2×4 measures 1.5" × 3.5" after milling, but lumber is priced at the nominal size. Using the actual dimensions gives a smaller number that no yard will recognise.
What does 4/4 or 8/4 mean for hardwood?
The thickness in quarter-inches before surfacing: 4/4 is one inch, 5/4 is one and a quarter, 8/4 is two inches. Hardwood is usually sold rough at these thicknesses and by the board foot.
How do I price a lumber order by board foot?
Total the board feet, then multiply by the price per board foot. One hundred and twenty board feet at $3.50 is $420 before tax and delivery.
Is a board foot the same as a linear foot?
No. A linear foot measures only length; a board foot measures volume. Twelve linear feet of 2×6 is 12 board feet, but 12 linear feet of 1×4 is only 4 board feet.