Board Feet Calculator
Calculate board feet for a piece of lumber using the standard formula: (thickness in inches × width in inches × length in inches) ÷ 144.
How the board footage is worked out
A board foot is 144 cubic inches of wood - one square foot of 1 inch thick stock. The tool multiplies your three dimensions and divides:
board feet = (thickness in × width in × length in) / 144
total = board feet × number of boardsWith the defaults of 1" × 6" × 96", that is 576 cubic inches, and 576 / 144 = 4.00 bf per board, and ten of them is 40.00 bf. If your length is in feet, multiply by 12 first - an 8 ft board is 96 in. All three dimensions must be positive or the tool returns an error instead of a total.
Use actual sizes, not nominal ones
Softwood is named for its rough-sawn size before drying and surfacing, so the board on the rack is smaller than the label says:
| Nominal | Actual |
|---|---|
| 1 × 6 | 0.75" × 5.5" |
| 2 × 4 | 1.5" × 3.5" |
| 2 × 10 | 1.5" × 9.25" |
A nominal 1 × 6 × 8 ft is 0.75 × 5.5 × 96 / 144 = 2.75 bf of real wood against the 4.00 bf its name implies - a third less. Enter actual sizes for what a project consumes, nominal ones only to check a yard's invoice.
Frequently asked questions
How many board feet is a 2x4x8?
3.50 bf of actual wood: 1.5 × 3.5 × 96 / 144. Priced at its nominal size it counts as 5.33 bf, which is why the same stick can be quoted two ways.
What is the difference between a board foot and a linear foot?
A linear foot counts length only, a board foot counts volume. An 8 ft 1 × 6 and an 8 ft 1 × 12 are both 8 linear feet, but the wider one is 8 nominal board feet against the other's four.
Does this include an allowance for waste?
No. It returns exact geometry, with nothing added for the roughly 1/8" your blade turns to dust at each cut, for jointing, or for knots and split ends. Order 15-20% over on dimensional stock, 30% or more on rough hardwood.