About the Board Foot Calculator
This board foot calculator converts the dimensions of a board — thickness and width in inches, length in feet — into board feet, the volume unit used to sell hardwood lumber and many rough-sawn softwoods in North America. One board foot is a piece 1 inch thick, 12 inches wide and 12 inches long, or 144 cubic inches.
Woodworkers use it to price walnut, oak or maple at the lumberyard, sawyers use it to tally logs cut on a portable mill, and builders use it to compare a per-board price with a per-board-foot quote. Enter the quantity and price per board foot and it totals the volume, the lumber cost and the linear footage of the order.
Hardwood is measured by its rough thickness in quarters (4/4 = 1 in, 8/4 = 2 in) and usually by actual width, whereas dimensional lumber such as a 2×6 is billed by nominal size even though it is planed smaller. Use the dimensions your supplier uses for billing.
With the default inputs, the total board feet is 80 BF. Change any value above to recalculate instantly.
How to use the board foot calculator
- 1Enter the board thickness in inches (4/4 = 1, 8/4 = 2).
- 2Enter the width in inches and the length in feet.
- 3Enter how many identical boards you are buying.
- 4Add the price per board foot to see the total cost.
- 5Repeat for each different board size and add the totals.
Formula and method
A board foot is 144 cubic inches — a board 1 in thick, 12 in wide and 12 in long. Multiplying thickness and width in inches by length in feet gives a figure in “inch-inch-feet”, and dividing by 12 converts it to board feet. (If all three dimensions are in inches, divide by 144 instead.)
Total board footage is the per-board figure times the number of boards, and cost is total board feet times the price per board foot. Twelve board feet make one cubic foot, and one board foot equals about 0.00236 cubic meters, which helps when comparing with suppliers that quote in metric.
- T
- Thickness (in), nominal or rough
- W
- Width (in)
- L
- Length (ft)
- BF
- Board feet (144 in³ each)
Worked examples
Ten 2×6 boards, 8 ft long
Each 2×6×8 is 2 × 6 × 8 ÷ 12 = 8 board feet, so ten boards total 80 BF. At $4 per board foot the order costs $320, and 80 BF is 6.67 cubic feet of wood.
Five 4/4 walnut boards, 8 in wide × 10 ft
A 1-inch walnut board 8 in wide and 10 ft long is 1 × 8 × 10 ÷ 12 = 6.67 BF. Five boards make 33.3 BF, which costs $400 at $12 per board foot.
One 8/4 oak slab, 10 in × 12 ft
Two inches thick by 10 in wide by 12 ft long gives 2 × 10 × 12 ÷ 12 = 20 board feet, or about 0.047 m³. At $9 per BF the slab costs $180.
Frequently asked questions
How do you calculate board feet?+
Multiply thickness (in) × width (in) × length (ft) and divide by 12. If you measure the length in inches too, divide by 144 instead. For example, a 1×12 board 1 ft long is exactly 1 board foot.
How many board feet are in a 2×4×8?+
Using nominal dimensions, a 2×4 that is 8 ft long is 2 × 4 × 8 ÷ 12 = 5.33 board feet. Its actual planed size is 1½ × 3½ in, but lumber is traditionally billed on nominal size.
What does 4/4 or 8/4 mean in hardwood?+
Hardwood thickness is expressed in quarters of an inch of rough-sawn thickness: 4/4 is 1 in, 5/4 is 1¼ in, 6/4 is 1½ in and 8/4 is 2 in. Board footage is calculated from these rough thicknesses.
How many board feet are in a cubic foot?+
There are 12 board feet in one cubic foot, because a cubic foot is 1,728 cubic inches and a board foot is 144 cubic inches. One cubic meter equals about 424 board feet.
Should I add extra for waste?+
Yes, when buying hardwood for furniture it is common to buy 20–30% more board feet than the finished parts require, to allow for defects, knots, planing and grain matching.