Board foot calculator
Thickness, width, length and quantity in. Board feet and cost out.
The formula
board feet = (thickness" × width" × length") ÷ 144
A board foot is 144 cubic inches, which is a piece one inch thick, twelve inches wide and one foot long. Because it is a volume and not an area, doubling the thickness doubles the price.
Quarter sizes, and the mistake that costs money
Hardwood is quoted in quarters of an inch of nominal thickness: 4/4 is one inch, 8/4 is two inches. The trap is that you are charged on the rough nominal size, not on what you get after surfacing. A 4/4 board planed to ¾" is still sold and billed as 4/4. Enter the nominal number the yard quoted, not the thickness you measure at home.
| Quarter | Nominal | Typical surfaced |
|---|---|---|
| 4/4 | 1" | 13/16" to 7/8" |
| 5/4 | 1 1/4" | 1 1/16" |
| 6/4 | 1 1/2" | 1 5/16" |
| 8/4 | 2" | 1 3/4" |
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