Board Foot Calculator
Work out how many board feet of lumber you're buying. Enter the thickness, width, and length of the boards and how many you need, plus the price per board foot if you want the total cost.
Board feet
8
Check the highlighted fields to see your result.
- Each board
- 8
- Cubic meters
- 0.0189
- Total cost
- —
Results are estimates for information only and do not constitute financial, medical, or legal advice.
How board feet work
Board feet measure the volume of wood. Multiply thickness and width in inches by length in feet, and divide by 12. That turns every board, whatever its shape, into a common unit you can price and compare.
The formula
Board feet = thickness (in) × width (in) × length (ft) ÷ 12
Worked example
You need ten 2×6 boards, 8 feet long, at $4.50 per board foot.
- One board: 2 × 6 × 8 ÷ 12 = 8 board feet.
- Ten boards: 80 board feet.
- Cost: 80 × $4.50 = $360.
Frequently asked questions
What is a board foot?
A unit of volume for lumber: a piece 1 inch thick, 12 inches wide, and 1 foot long, or 144 cubic inches. Hardwood and rough lumber are usually priced by the board foot.
Should I use nominal or actual dimensions?
Lumberyards usually price by nominal size, so a 2×6 counts as 2 × 6 inches even though it actually measures about 1½ × 5½. For rough-sawn hardwood, use the real thickness, often written in quarters: 4/4 is 1 inch, 8/4 is 2 inches.
Should I buy extra wood?
Yes. Knots, cracks, and cuts waste part of every board. Woodworkers usually add 15% to 30% for hardwood projects, depending on the wood's quality and the cut list.