A board foot is the unit lumber is measured and priced in: a piece 1 in thick, 12 in wide and 12 in long, or 144 cubic inches. The American Softwood Lumber Standard defines board measure as nominal thickness in inches times nominal width in feet times length in feet (PS 20, section 2.2). The formula in inches is thickness x width x length (ft) ÷ 12. The charts below give the board feet in common sizes and lengths so you can total a lumber list without a calculator; for odd sizes or a long list use the board foot calculator.
Board feet in softwood lumber by size and length
| Nominal size | Per linear foot | 6 ft | 8 ft | 10 ft | 12 ft | 14 ft | 16 ft | 20 ft |
|---|---|---|---|---|---|---|---|---|
| 1×4 | 0.33 | 2 | 2.67 | 3.33 | 4 | 4.67 | 5.33 | 6.67 |
| 1×6 | 0.5 | 3 | 4 | 5 | 6 | 7 | 8 | 10 |
| 1×8 | 0.67 | 4 | 5.33 | 6.67 | 8 | 9.33 | 10.67 | 13.33 |
| 1×10 | 0.83 | 5 | 6.67 | 8.33 | 10 | 11.67 | 13.33 | 16.67 |
| 1×12 | 1 | 6 | 8 | 10 | 12 | 14 | 16 | 20 |
| 2×4 | 0.67 | 4 | 5.33 | 6.67 | 8 | 9.33 | 10.67 | 13.33 |
| 2×6 | 1 | 6 | 8 | 10 | 12 | 14 | 16 | 20 |
| 2×8 | 1.33 | 8 | 10.67 | 13.33 | 16 | 18.67 | 21.33 | 26.67 |
| 2×10 | 1.67 | 10 | 13.33 | 16.67 | 20 | 23.33 | 26.67 | 33.33 |
| 2×12 | 2 | 12 | 16 | 20 | 24 | 28 | 32 | 40 |
| 4×4 | 1.33 | 8 | 10.67 | 13.33 | 16 | 18.67 | 21.33 | 26.67 |
| 4×6 | 2 | 12 | 16 | 20 | 24 | 28 | 32 | 40 |
| 6×6 | 3 | 18 | 24 | 30 | 36 | 42 | 48 | 60 |
| 6×8 | 4 | 24 | 32 | 40 | 48 | 56 | 64 | 80 |
Hardwood: board feet per linear foot by thickness and width
| Thickness | 4 in wide | 6 in wide | 8 in wide | 10 in wide | 12 in wide | 6 in x 8 ft board |
|---|---|---|---|---|---|---|
| 4/4 (1 in rough) | 0.33 | 0.5 | 0.67 | 0.83 | 1 | 4 |
| 5/4 (1.25 in rough) | 0.42 | 0.62 | 0.83 | 1.04 | 1.25 | 5 |
| 6/4 (1.5 in rough) | 0.5 | 0.75 | 1 | 1.25 | 1.5 | 6 |
| 8/4 (2 in rough) | 0.67 | 1 | 1.33 | 1.67 | 2 | 8 |
| 12/4 (3 in rough) | 1 | 1.5 | 2 | 2.5 | 3 | 12 |
Worked examples
- Framing a wall: 20 studs, 2×4 x 8 ft, are 20 x 5.33 = 106.67 board feet.
- Deck joists: 12 joists, 2×10 x 12 ft, are 12 x 20 = 240 board feet.
- A hardwood board: an 8/4 board 7 in wide and 9 ft long is 2 x 7 x 9 ÷ 12 = 10.5 board feet. Random-width hardwood is tallied board by board and the tally rounded by the seller’s rule, so your total may differ slightly from the invoice.
- Pricing: multiply board feet by the price per board foot, or divide a price per thousand board feet (MBM) by 1,000. The lumber cost calculator handles per-piece and per-board-foot prices.
Tips
- Plan for waste: planing rough hardwood to finished thickness and ripping off a straight edge typically loses a fifth or more of the volume; buy 15 to 30% extra for furniture projects.
- Board feet measure volume, not weight. To estimate the weight of a stack, multiply board feet by the pounds per board foot in the lumber weight chart.
- Sheet goods (plywood, MDF) are sold by the sheet, not by board foot.
- What the grades on a hardwood tally mean, FAS, Selects and No. 1 Common, is explained in lumber grades explained.
Frequently asked questions
How many board feet are in a 2x4x8?
5.33 board feet: 2 x 4 x 8 ÷ 12. Softwood is counted on nominal size.
How many board feet are in a 2x6x10?
10 board feet.
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, and divide by 12. For lengths in inches, divide by 144 instead.
How many board feet are in a 4x4x8?
10.67 board feet.
Is hardwood measured on rough or finished thickness?
Rough. A 4/4 board counts as 1 in thick even after it is surfaced to about 13/16 in.
Sources
- US Department of Commerce / NIST, PS 20-25, American Softwood Lumber Standard, section 2.2 (board measure).
- USDA Wood Handbook FPL-GTR-190, chapter 6 (hardwood thicknesses and random widths).
Last reviewed: 24 October 2026. Related: board foot calculator, lumber dimensions chart, lumber weight chart. Spotted an error? Please let us know.