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Board Foot Calculator
A board foot is the standard unit for pricing hardwood and rough lumber in the US and Canada. This calculator converts your board dimensions into board feet, totals them for any quantity, and estimates the cost at your price per board foot.
Results update as you type. Estimates only — confirm final quantities before ordering.
The formula
One board foot is a volume of 144 cubic inches — a piece 1 inch thick, 12 inches wide and 1 foot long. If all three dimensions are in inches, the equivalent formula is board feet = (thickness × width × length) ÷ 144. Multiply the per-piece result by the quantity for the total, and by your price per board foot for the cost. Lumber is normally tallied on its nominal size (a "2×4" counts as 2 in × 4 in even though it measures 1.5 × 3.5 in finished), which is the convention this calculator uses.
Worked example
Example: ten boards, each 2 in thick, 8 in wide and 8 ft long, at $4.50 per board foot.
- Per piece: (2 × 8 × 8) ÷ 12 = 10.67 bf
- Total: 10.67 × 10 pieces = 106.67 bf
- Cost: 106.67 × $4.50 = $480.00
Reference chart
| Nominal size | Board feet (8 ft piece) |
|---|---|
| 1×4 | 2.67 |
| 1×6 | 4.00 |
| 1×8 | 5.33 |
| 2×4 | 5.33 |
| 2×6 | 8.00 |
| 2×8 | 10.67 |
| 2×10 | 13.33 |
| 2×12 | 16.00 |
| 4×4 | 10.67 |
Frequently asked questions
What is a board foot?
A board foot is a unit of lumber volume equal to 144 cubic inches — the volume of a board 1 inch thick, 12 inches wide and 12 inches long. It is written as BF or FBM; 1,000 board feet is written MBF.
How many board feet are in a 2x4x8?
Using the nominal size the lumberyard prices by: (2 × 4 × 8) ÷ 12 = 5.33 board feet. Measured at its finished size (1.5 × 3.5 in) the same stud holds 3.5 board feet, which is why it pays to confirm your supplier's convention before a big order.
Should I enter nominal or actual dimensions?
Enter the nominal (label) size. Softwood dimensional lumber is sold and tallied on nominal dimensions, and hardwood is tallied on its rough-sawn thickness (4/4 = 1 in rough). Pricing on the rough/nominal size matches the invoice you will actually receive.
How much extra should I buy for waste?
Add roughly 10–15% for straight cuts and general work, 15–25% for furniture joinery, and up to 30% for rough-sawn hardwood you will mill and grain-match yourself. Board feet measure volume, not usable yield — knots, checks and offcuts all consume stock.
What is the difference between board feet and linear feet?
Linear feet measure length only; board feet measure volume. A 4-inch-wide board and a 12-inch-wide board of the same length have identical linear feet but the wider board has three times the board feet — and costs proportionally more.
Related calculators
- Drywall Calculator — Sheets of 4×8 and 4×12 drywall for your wall and ceiling area.
- Fence Calculator — Posts, sections, rails and pickets for a wood fence.
- Concrete Calculator — Cubic yards and bag counts for slabs, patios and pads.
Sources & method: NHLA board-foot formula (thickness × width × length ÷ 144 in³); Omni Calculator — Board Foot Calculator; nominal-vs-actual convention per American Lumber Standard PS 20.