Board Foot Calculator
Lumber volume & cost — instant results
How to use this board foot calculator
Enter the thickness, width, and length of your lumber, and this calculator does the board foot math instantly. Add more boards with the “+ Add another board” button if you’re pricing out a whole order — the total updates as you go. Switch to metric if you’re working in centimeters.
Board foot formula
A board foot is a unit of volume, not area — it accounts for thickness as well as length and width. That’s the whole reason it exists instead of just using square footage.
So an 8-foot board that’s 6 inches wide and 1 inch thick works out to (1 × 6 × 8) ÷ 12 = 4 board feet. Nominal 2x lumber (a “2×4”) uses the stamped nominal size for this math even though the actual milled dimensions are smaller — that’s the standard trade convention, so this calculator follows it too.
Why this matters before you buy
Hardwood is priced per board foot, not per piece — so eyeballing “I need about 5 boards” can leave you short or paying for way more than the project needs. Running the numbers first means one trip to the lumber yard instead of two.