Quick Answer
A board foot is 144 cubic inches of wood. A piece measuring 1 inch thick × 12 inches wide × 12 inches long equals 1 board foot.
Formula: Board feet = Thickness (in) × Width (in) × Length (ft) ÷ 12 × Quantity
For lengths that include inches, this calculator converts the full length to inches automatically.
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Board Foot Calculator
Board Foot Formula
When length is entered in feet, the standard board-foot calculation is:
Multiply the result by the number of identical pieces to calculate the total board feet.
Actual vs Nominal Dimensions
Board-foot totals depend on the dimensions you enter. For a true volume calculation, use actual measured dimensions. If your supplier prices rough lumber using nominal or rough dimensions, use the same dimensions the supplier uses so your estimate matches the invoice method.
Board Feet and Cubic Feet
One board foot equals 144 cubic inches. One cubic foot equals 1,728 cubic inches, so one cubic foot contains 12 board feet.
Estimating Lumber Cost
If lumber is sold by the board foot, multiply total board feet by the supplier's price per board foot. Species, grade, thickness, drying, surfacing, and local availability can all affect the price.
Board Foot Calculator FAQ
What is a board foot?
A board foot is a unit of lumber volume equal to 144 cubic inches. A board measuring 1 inch thick, 12 inches wide, and 12 inches long contains exactly 1 board foot.
How do you calculate board feet?
Multiply the board's thickness in inches by its width in inches by its length in feet, then divide by 12. For multiple identical boards, multiply by the number of pieces.
Should I use actual or nominal lumber dimensions?
Use actual measured dimensions when you want the true volume of finished or dressed lumber. If you are estimating the purchase price of rough lumber, use the dimensions and board-foot convention used by your supplier.
How many board feet are in one cubic foot?
There are 12 board feet in one cubic foot.
How much is a board foot of lumber?
The price varies by wood species, grade, thickness, moisture condition, surfacing, and market. Enter the current price per board foot in the calculator to estimate your total material cost.
Can I calculate several identical boards at once?
Yes. Enter the dimensions of one board and then enter the total number of pieces. The calculator reports both board feet per piece and total board feet.