Board Foot Calculator — Lumber Volume
A board foot is the standard volume unit for rough lumber. Enter the nominal thickness and width in inches and the length in feet (or inches) to instantly calculate board feet, cubic inches and cubic meters for one or more boards.
in
in
Length unit
pcs
Volume of one board in the standard lumber unit
- 1
Multiply dimensions
1 × 6 × 8 = 48 - 2
Board feet per piece
48 ÷ 12 = 4Dividing by 12 converts thickness × width × length-in-feet to board feet.
How does this calculator work?
Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. All dimensions must use inches for thickness and width; divide by 144 instead of 12 if length is also in inches. Multiply by 0.002359737 to convert board feet to cubic meters. Always order 10–15% extra for waste.
Formula
How this is calculated
A board foot equals a piece of lumber 1 inch thick, 12 inches wide, and 1 foot long — that is, exactly 144 cubic inches. The formula multiplies the nominal thickness (in inches) by the nominal width (in inches) by the length, then divides by 12 if the length is in feet, or by 144 if all three dimensions are in inches. For example, a 1 × 6 × 8 ft board is (1 × 6 × 8) / 12 = 4 BF.
Lumber is almost always priced on nominal rather than actual dressed dimensions, so enter the nominal size your supplier quotes. For multiple identical boards, multiply the per-piece result by the quantity to get the total board footage. The metric volume is obtained by multiplying total board feet by the exact conversion factor 0.002359737 m³/BF (since 1 BF = 144 in³ and 1 in³ = 16.387064 cm³).
This calculator assumes straight, rectangular boards. It does not account for bow, warp or waste from defects. Always add 10–15% to the calculated total when ordering to cover waste from cutting, knots, and end checks.
Frequently asked questions
A board foot is 144 cubic inches of wood — equivalent to a board 1 in × 12 in × 1 ft. Suppliers use it because it lets them price any size of rough lumber on a single volumetric basis, so a thick narrow board and a thin wide board of the same volume cost the same per BF.
Use nominal dimensions — the size the board is sold as (e.g. 2 × 4) — because that is what suppliers use to price and label lumber. A dressed 2 × 4 is actually about 1.5 × 3.5 in, but it is priced and billed as 2 × 4 nominal.
A standard allowance is 10–15% above the calculated board footage for waste, defects, end cuts, and measurement errors. For projects with complex cuts or large knots, go to 20%.
TG we-Calculate Editorial Team. (2026). Board Foot Calculator — Lumber Volume [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/board-foot-calculator
TG we-Calculate Editorial Team. "Board Foot Calculator — Lumber Volume." TG we-Calculate. 2026. https://we-calculate.com/calculator/board-foot-calculator.
TG we-Calculate Editorial Team, "Board Foot Calculator — Lumber Volume," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/board-foot-calculator
@misc{wecalculate_board_foot_calculator, title = {Board Foot Calculator — Lumber Volume}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/board-foot-calculator}}, year = {2026}, note = {TG we-Calculate} }
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