What Is a Board Foot?
A board foot is a unit of volume equal to a piece of lumber 12 inches long, 12 inches wide, and 1 inch thick. That is 144 cubic inches of wood. It is the standard unit of measure used across the lumber industry — new and reclaimed — for pricing, inventory, and quantity estimation.
The formula for calculating board feet is straightforward: thickness (in inches) multiplied by width (in inches) multiplied by length (in feet), divided by 12. For example, a board that is 1 inch thick, 8 inches wide, and 10 feet long contains (1 x 8 x 10) / 12 = 6.67 board feet.
Nominal vs. Actual Dimensions
One source of confusion is the difference between nominal and actual dimensions. In the new lumber industry, a "1-inch" board is actually 3/4 inch thick after planing, and a "2-inch" board is actually 1-1/2 inches thick. Board footage is calculated using nominal dimensions for new lumber.
Reclaimed lumber is different. Because reclaimed boards come in non-standard dimensions — a reclaimed floor joist might be 1-7/8 inches thick, or a barn board might be 7/8 inch thick — board footage is typically calculated using actual measured dimensions rather than nominal sizes. This means you get what you pay for: if a reclaimed board measures 1-1/2 inches thick, you are paying for 1-1/2 inches of wood, not a rounded-up nominal dimension.
Calculating Board Feet for Common Reclaimed Products
Boards and Planks
For individual boards and planks, measure the thickness and width in inches and the length in feet, then apply the formula. If a reclaimed heart pine plank is 1 inch thick, 10 inches wide, and 8 feet long, the board footage is (1 x 10 x 8) / 12 = 6.67 board feet.
For multiple boards of the same dimensions, multiply the per-board calculation by the number of boards. Ten boards of the same dimensions as above would total 66.7 board feet.
Timbers and Beams
Timbers follow the same formula, but the numbers get larger quickly. A reclaimed 8x8 timber that is 12 feet long contains (8 x 8 x 12) / 12 = 64 board feet. A single large timber can represent significant board footage and significant value.
Flooring and Paneling
Flooring and paneling are sometimes sold by the board foot and sometimes by the square foot. When sold by the square foot, the calculation accounts for the installed coverage area, which is less than the total board footage because tongue-and-groove profiles reduce the exposed face width. A 4-inch tongue-and-groove board has a face coverage of approximately 3-1/4 inches after the tongue is hidden by the groove of the adjacent board.
When comparing prices, make sure you know whether the price is per board foot (total volume) or per square foot (installed coverage). The per-square-foot price will always be higher than the per-board-foot price for the same material because you need more board feet to cover a square foot of surface.
Estimating Material for a Project
Flooring
To estimate reclaimed flooring material, calculate the square footage of your floor area and add 15% to 20% for waste and cutting. Divide by the face coverage width of your flooring to determine the total linear footage needed, then convert to board feet. Or simply tell us your floor dimensions and the board width you prefer, and we will calculate the order for you.
Accent Walls and Paneling
Calculate the wall area in square feet and add 10% to 15% for waste. For random-width installations, the waste factor can be lower because short and narrow pieces can fill gaps. For uniform-width installations, the waste factor should be higher because each cut-off is a loss.
Structural Timbers
For timber orders, provide the required dimensions (cross-section and length) and quantity. We will calculate the board footage and price. When possible, provide a range of acceptable dimensions — for example, "8x8 to 8x10, 10 to 12 feet long" — to give us flexibility in matching your order from available inventory.
How Board Footage Affects Pricing
Reclaimed lumber is priced per board foot, with the rate varying by species, grade, dimensions, and processing. Here are approximate price ranges for common reclaimed products at Norfolk Lumber:
- Reclaimed heart pine: $8 to $18 per board foot, depending on grade and width
- Reclaimed white oak: $6 to $14 per board foot
- Reclaimed mixed hardwood: $4 to $10 per board foot
- Reclaimed softwood (SYP, Douglas fir): $3 to $8 per board foot
- Reclaimed American chestnut: $12 to $25 per board foot
- Reclaimed cypress: $7 to $15 per board foot
Custom milling (resawing, planing, tongue-and-groove profiling) adds to the base material cost, typically $0.50 to $2.00 per board foot depending on the operation. Kiln drying adds approximately $0.50 per board foot.
Making It Simple
If the board foot calculation feels overwhelming, do not worry — that is what we are here for. Give us your project dimensions and requirements, and our team will calculate the material quantity, provide a price quote, and help you plan your order. We deal in board feet every day so you do not have to.