Board Foot Calculator
Calculate board feet of lumber from thickness, width, length, and quantity, plus total cost at your price per board foot. For hardwood and rough lumber pricing.
How this calculator works
Board feet measure the volume of a board, so the same total can come from many different board sizes. Enter thickness and width in inches, length in feet, and how many identical boards you have; the calculator returns total board feet and cost.
Formula: Board feet = (thickness in × width in × length ft) ÷ 12, times the number of boards.
Worked example
Ten 2×6 boards, each 8 feet long, at $4 per board foot:
- Per board: (2 × 6 × 8) ÷ 12 = 8 BF
- Total: 8 × 10 = 80 BF
- Cost: 80 × $4 = $320.00
Reference
| Board | Board feet each (8 ft) |
|---|---|
| 1×4 | 2.67 BF |
| 2×4 | 5.33 BF |
| 2×6 | 8.00 BF |
| 2×8 | 10.67 BF |
How to measure
Measure each board’s actual thickness and width in inches and its length in feet. For hardwood priced by the quarter (4/4, 6/4, 8/4), enter the nominal thickness that quarter represents so your board-foot total matches the yard’s bill.
Frequently asked questions
What is a board foot?
A board foot is a volume unit for lumber: 144 cubic inches, equal to a 1-inch-thick, 12-inch-wide, 12-inch-long board. Hardwood and rough-sawn lumber are almost always priced per board foot rather than per piece, because thickness and width vary.
Do I use nominal or actual thickness?
For rough-sawn lumber, use the actual measured dimensions. For surfaced hardwood sold by the board foot, suppliers usually bill on the nominal (pre-planing) thickness in quarters — 4/4 means one inch, 8/4 means two inches — so use that nominal figure to match your quote.
Why is length in feet but thickness and width in inches?
That is the standard board-foot convention and why the formula divides by 12: thickness (in) × width (in) × length (ft) ÷ 12. Mixing the units this way is exactly how lumber yards quote it.
How do I price a mixed pile of lumber?
Board feet add up regardless of piece size, so total the board feet of every board and multiply once by your price per board foot. Run this calculator once per distinct board size and sum the totals.
Does board foot apply to plywood or sheet goods?
No — plywood, OSB, and other sheet goods are sold by the sheet or square foot, not the board foot. Use the Plywood Calculator for those.
Estimates only. Verify quantities with your supplier before purchasing.