Board Foot Calculator
Figure board feet and total cost before you get to the lumber yard. Enter rough thickness, width, and length, or tap a quarter preset.
Per board
4 bd ft
Total (1 boards)
4 bd ft
Estimated cost
--
How the math works
One board foot is 144 cubic inches of wood: a board 1 inch thick, 12 inches wide, and 12 inches long. The formula is thickness times width times length (all in inches), divided by 144. This calculator handles the unit conversion when your length is in feet.
Hardwood dealers price rough lumber in quarters: 4/4 is 1 inch, 8/4 is 2 inches, and so on. Use the rough thickness even if the board has been surfaced thinner. That is the number the yard will charge you for.
FAQ
- What is a board foot?
- A board foot is a unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long, or 144 cubic inches. Hardwood is usually priced per board foot rather than per piece.
- What is the board foot formula?
- Board feet = (thickness in inches x width in inches x length in inches) / 144. If length is in feet, use (thickness x width x length in feet) / 12.
- Do I use nominal or actual thickness?
- Board feet are calculated from the rough-sawn (nominal) thickness before surfacing. A surfaced board measuring 3/4 inch thick is sold as 4/4 (1 inch) because that was its rough thickness.
- How many board feet are in a 2x4x8?
- Using nominal dimensions: 2 x 4 x 96 / 144 = 5.33 board feet. Construction lumber is normally priced per piece, though, so board feet mostly matter for hardwood.