About this tool
Board Foot Calculator is a free, in-browser tool that computes the board footage of lumber — the volume unit hardwood is priced by — from a board's thickness, width and length, for any number of identical boards. All figures are computed locally as you type; nothing is uploaded.
One board foot is 144 cubic inches of wood, equal to a piece 1 inch thick, 12 inches wide and 1 foot long. When length is in feet, board feet = thickness × width × length ÷ 12 per board; when length is in inches, board feet = thickness × width × length ÷ 144. Thickness and width are always in inches. Multiply by the quantity for the total, and if you enter a price per board foot the tool multiplies it out to a total cost.
Use it at the lumberyard to compare prices and size an order: rough hardwood is sold by the board foot in quarter thicknesses (4/4 = 1 inch, 8/4 = 2 inches), so this is the figure you multiply by the per-board-foot price.
Frequently asked questions
What exactly is a board foot?
It is 144 cubic inches of lumber — the volume of a board 1 inch thick, 12 inches wide and 12 inches (one foot) long. It measures volume, not surface area, so thickness matters as much as width and length.
Why are there two length units?
Lumber length is quoted in feet at the yard but sometimes in inches for offcuts. With feet the divisor is 12; with inches it is 144. Thickness and width stay in inches either way, so pick the toggle that matches your measurement.
Should I use rough or finished thickness?
Board feet are normally figured from the rough (nominal) thickness — for example 4/4 counts as 1 inch even after planing to 3/4 inch. Use the thickness your supplier bills by to match their price per board foot.
How is the total cost figured?
If you enter a price per board foot, the cost is total board feet × that price. Leave the price blank to see board feet only. Everything is computed in your browser and nothing is uploaded.
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