Board Foot Calculator
Use this board foot calculator to estimate lumber volume in board feet and multiply it by a price rate to estimate the total cost.
Board Foot Result
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Quick Answer: Board feet are calculated with thickness x width x length x pieces / 12 when thickness and width are in inches and length is in feet.
How to Calculate
- Enter lumber size: Provide the board thickness, width, and length in the standard board-foot units.
- Enter piece count: Add the number of identical pieces you are pricing.
- Enter unit price: Use the cost per board foot from your supplier quote.
- Review volume and cost: The calculator returns both the total board feet and the estimated total cost.
Formula
board feet = thickness x width x length x pieces / 12
| Variable | Meaning | Unit |
|---|---|---|
| thickness | Board thickness | in |
| width | Board width | in |
| length | Board length | ft |
| pieces | Number of boards | count |
Worked Examples
Lumber order - Pricing several planks
- Thickness: 2 in
- Width: 8 in
- Length: 12 ft
- Pieces: 5
Result: Board feet = 80
At $4.50 per board foot, the lumber cost would be $360.
Interpretation Table
| Range | Meaning | Action |
|---|---|---|
| Higher board-foot value | More lumber volume | Expect higher cost and shipping weight. |
| Lower board-foot value | Less lumber volume | Double-check whether nominal versus actual dimensions affect your estimate. |
| Higher price per board foot | More expensive species or grade | Verify grade, moisture content, and waste allowance before ordering. |
Frequently Asked Questions
A board foot is a volume of lumber equal to a board 1 inch thick, 12 inches wide, and 1 foot long.
The factor of 12 converts the inch-inch-foot volume into board-foot units.
Use whichever dimensions you need for your estimate, but be consistent. Supplier pricing often follows nominal sizing.
Note: This calculator estimates board feet and material price only. Final purchasing should also consider trim loss, defects, grade, taxes, and shipping.
References
Last reviewed: March 14, 2026