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Board Foot Calculator
Our free board foot calculator works out how many board feet are in a piece of lumber, or in a whole stack of identical pieces. Enter the thickness, width, length, and piece count, and it gives you the total board feet plus an estimated cost in US dollars.
US hardwoods often run $3–$8 per board foot. Estimates only.
| Board feet per piece | |
| Number of pieces | |
| Total volume (cubic feet) | |
| Estimated cost |
How it works
A board foot is the standard unit for measuring and pricing lumber in the United States, especially hardwood. One board foot is the volume of a board that is 1 inch thick, 12 inches wide, and 1 foot long. That works out to 144 cubic inches. If you have ever wondered why a lumberyard quotes walnut at $12 per board foot instead of per board, this is why: the price follows the volume of wood, not the shape of the piece.
To use the calculator, enter the thickness in inches, the width in inches, and the length in feet. These are the nominal sizes printed on the board, such as 2 by 6, not the actual planed measurements. A 2 by 4 actually measures about 1.5 by 3.5 inches, but it is sold, priced, and calculated as a 2 by 4. Then enter how many identical pieces you need, and an optional price per board foot if you want a cost estimate.
Total board feet = Board feet per piece × Number of pieces
The division by 12 does two jobs at once: it turns the 12-inch width into 1 foot and keeps the length in feet, so the result is a volume in board feet. A neat shortcut is that a board 1 inch thick and 12 inches wide contains exactly 1 board foot per foot of length. Double the thickness or double the width and you double the board feet. The calculator also shows the total in cubic feet, which is simply the board feet divided by 12, in case you are comparing lumber with sheet goods or working out storage space.
Hardwood dealers in the US usually sell rough-sawn lumber by the board foot and round the total up, because rough boards are sold in random widths and lengths. Home centers, by contrast, sell softwood studs and pine boards by the piece, so the board-foot price matters less there. Either way, knowing the board feet lets you compare quotes fairly: a cheaper price per board foot is a cheaper board, whatever the size.
Worked example
Say you are building a workbench in your garage in Michigan and you need ten boards, each 2 inches thick, 6 inches wide, and 8 feet long. Here is the math for one board, step by step.
Multiply thickness by width by length: 2 × 6 × 8 = 96. Divide by 12: 96 ÷ 12 = 8 board feet per board. That is the exact result this calculator gives for a single 2 by 6 by 8 board. For ten identical boards, multiply by the piece count: 8 × 10 = 80 board feet in total. At $3 per board foot, the lumber costs about $240. The total volume is 80 ÷ 12 = 6.67 cubic feet of wood.
Try another common size. A 1 by 12 board that is 10 feet long contains 1 × 12 × 10 ÷ 12 = 10 board feet. A 4 by 4 post that is 8 feet long contains 4 × 4 × 8 ÷ 12 = 10.67 board feet. Once you see the pattern, you can estimate most boards in your head: a 2 by 4 that is 8 feet long is 2 × 4 × 8 ÷ 12 = 5.33 board feet, so a bundle of twelve studs is about 64 board feet.
FAQ
What is a board foot?
A board foot is a unit of lumber volume equal to a board 1 inch thick, 12 inches wide, and 1 foot long, which is 144 cubic inches. It is the standard way hardwood lumber is measured and priced in the United States.
How many board feet are in a 2x6x8 board?
A 2 by 6 inch board that is 8 feet long contains 8 board feet. The math is 2 times 6 times 8, divided by 12, which equals 8. Note that this uses the nominal size printed on the board.
Do I use nominal or actual lumber sizes?
Board feet are almost always calculated from nominal sizes, the size printed on the board, such as 2x4 or 1x6. A 2x4 actually measures about 1.5 by 3.5 inches after planing, but it is still sold and priced as a 2x4, so use the nominal size.
How much does lumber cost per board foot?
Common US hardwoods such as red oak and maple often run about $3 to $8 per board foot at a hardwood dealer, while walnut can be $10 to $15 or more. Softwood from a home center is usually cheaper. Prices vary by species, grade, and region.
How do I calculate board feet for many pieces?
Work out the board feet for one piece, then multiply by the number of identical pieces. For example, ten 2x6x8 boards at 8 board feet each come to 80 board feet in total. Enter the piece count in the calculator above and it does this for you.