To calculate board feet, multiply a board’s thickness in inches by its width in inches by its length in feet, then divide by 12; multiply by the number of boards for a total, and by your price per board foot for a cost.
Board Feet Calculator
Board feet of lumber from thickness, width and length — and price from your cost per board foot.
Estimating Board Feet and Lumber Cost
This board feet calculator converts a board’s thickness, width and length into board feet — the standard unit lumber yards and suppliers use for pricing rough-sawn and hardwood lumber — then multiplies by your price per board foot to estimate total cost. It works for a single board or a whole order by entering the number of identical boards.
This covers related searches such as how to calculate board feet, board foot formula, and lumber cost per board foot calculator.
How the Board Feet Calculator Works
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
Total board feet = Board feet per board × Number of boards
Total cost = Total board feet × Price per board foot
Where:
- Thickness = the board’s nominal thickness in inches
- Width = the board’s nominal width in inches
- Length = the board’s length in feet
Worked Example
A 1 in × 6 in board, 8 ft long: Board feet = (1 × 6 × 8) ÷ 12 = 4 board feet. For 10 such boards at $3.50 per board foot: Total = 4 × 10 × 3.5 = $140.
Frequently Asked Questions
What is a board foot?
A board foot is a unit of lumber volume equal to a piece of wood 1 inch thick, 12 inches wide, and 12 inches long — it measures volume, not just length, which is why thickness and width both factor into the calculation.
How do I calculate board feet by hand?
Multiply thickness (inches) by width (inches) by length (feet), then divide by 12 — that gives board feet for one piece; multiply by the number of identical pieces for a total.
Why is lumber priced by the board foot instead of linear foot?
Board footage accounts for both the width and thickness of the lumber, not just its length, which matters for hardwood and rough-sawn lumber sold in varying widths and thicknesses — dimensional softwood lumber is more commonly priced by the linear or running foot instead.
Does nominal size match actual size?
No — a board sold as “2×6” or “1×6” (nominal size) is typically smaller in actual dimension after milling and drying, so check with your supplier whether their board foot calculation uses nominal or actual dimensions.
How much does lumber cost per board foot?
Price per board foot varies enormously by species, grade, and current market conditions, so enter the price your specific supplier has quoted rather than assuming a fixed rate.
Is board footage the same for hardwood and softwood lumber?
The board foot formula itself is identical regardless of species — it’s purely a volume calculation from thickness, width and length. What differs between hardwood and softwood is typically the price per board foot and how the lumber is graded and sold.
Do kiln-dried and green lumber use the same board foot count?
Board footage is generally measured at the lumber’s nominal or rough-sawn dimensions at the time of sale, so ask your supplier whether their quoted board footage accounts for shrinkage from drying if that distinction matters for your order.
