Board Foot Calculator
Board feet and cost for rough lumber.
How it works
A board foot is 144 cubic inches — one foot square by one inch thick. The formula is thickness x width x length / 12, with thickness and width in inches and length in feet.
Two things catch people out. Hardwood is sold by nominal rough thickness in quarters — 4/4 is one inch, 8/4 is two — and you are charged for the rough dimension even though surfacing takes it down to about 13/16. And nominal softwood sizes are not real: a 2x4 measures 1½ by 3½.
Fifteen per cent waste is modest for anything involving grain matching or defect cutting.