Board Foot Calculator (Lumber)
Board feet are how rough and dimensional lumber gets priced — not by the piece, not by the linear foot. Enter thickness, width, length, and quantity and get the total board feet for the order. The math updates as you type.
Board Foot Calculator
One board foot is 12″ × 12″ × 1″ of lumber. Enter your dimensions per piece and how many pieces you need.
Board feet = (thickness × width × length) ÷ 12, with thickness and width in inches and length in feet. Rough-sawn stock is often sold and priced by nominal size, not actual milled size — confirm with your yard.
How to calculate board feet
The board foot formula converts a piece of lumber into a single volume unit: thickness (in) × width (in) × length (ft), divided by 12. Multiply the per-piece result by quantity to get the total for an order.
| Step | Example: 1″ × 6″ × 8’ board |
|---|---|
| Thickness × width × length | 1 × 6 × 8 = 48 |
| Divide by 12 | 48 ÷ 12 = 4 board feet per piece |
| × 10 pieces | 4 × 10 = 40 board feet total |
Lumber yards quote per board foot, so this number is what you take to the counter or use to compare pricing between species and grades. For sheet goods like plywood and OSB, yards typically quote by the sheet instead — the board foot formula applies to dimensional and rough-sawn lumber.
Contractor Estimate Calculator (Excel & Google Sheets)
Turn the board foot total into a priced, itemized estimate — materials, labor, markup, and profit, auto-totaled. The estimate you hand the client after the calculator tells you the quantity.
Nominal vs. actual size
A board sold as a “2×6” does not actually measure 2″ × 6″ once it is dried and planed — it is closer to 1.5″ × 5.5″. Rough-sawn and hardwood lumber, though, are usually priced and measured at nominal (pre-milling) size. Use the actual dimension in this calculator if your yard prices by actual size, and confirm which convention your supplier uses before you order.
Once the order is sized, price the job
The calculator gives you the board footage; your bid still needs labor, waste, and hardware. Price the full job with a construction estimate template, then send it with an itemized invoice once the work is done.
Frequently asked questions
What is a board foot?
A board foot is a volume of lumber equal to 12″ × 12″ × 1″ — 144 cubic inches. It is the standard unit lumber yards use to price dimensional and rough-sawn lumber, regardless of the actual shape of the piece.
How do you calculate board feet?
Multiply thickness (in) × width (in) × length (ft), then divide by 12. A 1″ × 6″ × 8’ board is (1 × 6 × 8) ÷ 12 = 4 board feet.
Is board foot the same as square foot?
No. Square footage measures area with no thickness. Board footage measures volume and accounts for thickness, which is why it is used for lumber pricing instead of area.
Is this board foot calculator free?
Yes — free, no sign-up. Enter thickness, width, length, and quantity and read the total board feet. Estimates only; confirm pricing convention with your lumber yard.