What is a board foot?

A board foot is a unit of lumber volume equal to a board 1 inch thick, 12 inches wide, and 12 inches long — that is, 144 cubic inches. Hardwood is almost always sold by the board foot rather than by length.

What is the board foot formula?

Board feet equal thickness in inches times width in inches times length in feet, divided by 12. If your length is in inches instead, multiply by length and divide by 144. The result is the same volume measured in board feet.

Should I use nominal or actual thickness?

Lumber is priced and tallied at its rough nominal thickness before surfacing, so use the nominal figure (for example 4/4 hardwood counts as 1 inch even though it dresses to about 13/16 inch). Width and length use rough dimensions too.

How do I convert board feet to cubic feet?

One board foot is 144 cubic inches and one cubic foot is 1728 cubic inches, so one cubic foot equals exactly 12 board feet. Divide board feet by 12 to get cubic feet, and multiply cubic feet by about 0.0283 to get cubic metres.

Does the calculator handle a mixed cut list?

Yes. Add as many different board sizes and quantities as you need and the running total tallies every piece. This is the same way a lumber yard tallies a mixed order before pricing it per board foot.

Board Feet Calculator

A board foot is the standard volume unit for selling rough lumber, especially hardwood. This calculator applies the board-foot formula to a single board or a full mixed cut list, then expresses the total in board feet, cubic feet, and cubic metres so you can place or price an order with confidence.

How it works

Every piece is reduced to a volume in board feet, where one board foot is a board 1 inch thick by 12 inches wide by 12 inches long:

board feet (one piece)  = (thickness_in × width_in × length_ft) / 12
board feet (a quantity) = board feet × pieces

The grand total is then converted to other volume units using fixed ratios:

cubic feet   = total board feet / 12
cubic metres = cubic feet × 0.0283168

Because one cubic foot is exactly 12 board feet, those conversions are exact — there is no rounding hidden inside them.

Example and tips

Eight pieces of 4/4 oak, 6 inches wide and 8 feet long, tally as (1 × 6 × 8) / 12 = 4 board feet each, or 32 board feet for the lot — about 2.67 cubic feet. Always count thickness at the nominal rough size: 4/4 stock is 1 inch and 8/4 stock is 2 inches for tally purposes, even though both dress thinner after planing. For length given in inches, the tool internally divides by 144 instead of 12 so the math stays correct.