Hardwood is not sold by the plank or by the square foot — it is sold by volume. The unit is the board foot: 144 cubic inches of wood, the volume of a board one foot square and one inch thick.
The formula
Board feet = length × width × thickness, all in inches, divided by 144. A 24 × 24 inch tabletop at 1 3/4 inches thick works out to 24 × 24 × 1.75 ÷ 144 — exactly 7 board feet. Double the length and the board footage doubles with it; specify a thicker top and the volume, and the material, grows in exact proportion.
Why it makes custom pricing honest
Because board footage scales perfectly with size, a price built on it never punishes or rewards a dimension arbitrarily. At Formhaus every price is built the same way: the board footage of your exact piece times the species' material cost, plus the same manufacturing value — milling, joinery, finishing — applied to every species equally. Choosing walnut over maple moves only the material line. The work is the work.
Where you'll see it
The configurator computes board footage live as you move the sliders, and the lumber line is quoted in it directly — supply orders start at 100 BF. Once you can read the unit, a hardwood price stops being a mystery and becomes arithmetic.