Board Foot Calculator
Work out board feet and cost for framing lumber, rough hardwood sold in quarters, or standing logs. Enter the size and count to get board feet, total length, volume and price per board and per linear foot.
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Board feet = thickness (in) × width (in) × length (ft) ÷ 12. A 2×6 that is 8 ft long is 2 × 6 × 8 ÷ 12 = 8 board feet, so ten of them are 80 BF. One board foot is 144 cubic inches: a piece 1 in thick, 12 in wide and 1 ft long.
How to use this board foot calculator
- Pick what you are measuring. Use Lumber for dimensional softwood (2×4, 2×6, 4×4), Hardwood for rough boards sold as 4/4, 8/4 and so on, or Log scale to estimate lumber in a log.
- Enter thickness and width in inches and length in feet. For framing lumber, use the nominal size (2 × 4, not 1½ × 3½).
- Enter the number of pieces and your yard’s price per board foot.
- Read the result: total board feet, cost, cost per board and per linear foot, and the same board at other common lengths.
Board feet in common lumber sizes
| Size | BF per linear ft | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|---|
| 1×4 | 0.33 | 2.67 | 3.33 | 4.00 | 5.33 |
| 1×6 | 0.50 | 4.00 | 5.00 | 6.00 | 8.00 |
| 2×4 | 0.67 | 5.33 | 6.67 | 8.00 | 10.67 |
| 2×6 | 1.00 | 8.00 | 10.00 | 12.00 | 16.00 |
| 2×8 | 1.33 | 10.67 | 13.33 | 16.00 | 21.33 |
| 2×10 | 1.67 | 13.33 | 16.67 | 20.00 | 26.67 |
| 2×12 | 2.00 | 16.00 | 20.00 | 24.00 | 32.00 |
| 4×4 | 1.33 | 10.67 | 13.33 | 16.00 | 21.33 |
| 6×6 | 3.00 | 24.00 | 30.00 | 36.00 | 48.00 |
To turn a price per board foot into a price per piece, multiply by the board feet in that piece. At $1.00 per BF, a 2×10 × 12 ft costs about $20.
Nominal vs actual size
Softwood framing lumber is named and counted by its nominal size, the rough size before drying and planing. The board you take home is smaller, but board feet and prices still use the nominal figures.
| Nominal | Actual (in) | Nominal | Actual (in) |
|---|---|---|---|
| 1×4 | ¾ × 3½ | 2×8 | 1½ × 7¼ |
| 1×6 | ¾ × 5½ | 2×10 | 1½ × 9¼ |
| 2×4 | 1½ × 3½ | 2×12 | 1½ × 11¼ |
| 2×6 | 1½ × 5½ | 4×4 | 3½ × 3½ |
Hardwood: board feet by the quarter
Hardwood yards sell rough lumber by thickness in quarter inches and measure it on the rough size. A 4/4 board is 1 in thick and usually planes to about 13/16 in. 8/4 is 2 in rough and planes to about 1¾ in. Widths and lengths vary board by board, so yards tally each board’s board feet and add them up. Buy 20–30% more than your cut list to allow for defects, planing and offcuts.
Log scale: Doyle and Scribner
Log rules estimate the lumber a mill can saw from a log, measured by the diameter inside the bark at the small end (D, inches) and length (L, feet).
The Doyle rule gives low figures for small logs, which favors the buyer. Scribner reads higher on small and medium logs and is used mainly in the western US. Check which rule your mill or forester uses before comparing prices.
Worked example
- Walnut, 8/4 × 7 in × 9 ft, 3 boards
- 2 × 7 × 9 ÷ 12 = 10.5 BF each
- Total
- 31.5 BF
- At $14 per BF
- $441 ($147 per board)
Frequently asked questions
How do you calculate board feet?
Thickness (in) × width (in) × length (ft) ÷ 12. A 2×6 × 8 ft is 8 board feet.
How many board feet are in a 2×4×8?
5.33 BF (2 × 4 × 8 ÷ 12). Softwood is counted on its nominal size, not the actual 1½ × 3½ in.
What is the difference between board feet and linear feet?
Linear feet are length only. Board feet are volume: one BF is 144 cubic inches. A 1×12 has 1 BF per linear foot, and a 2×4 has 0.67.
How do I convert board feet to cubic feet or cubic metres?
Divide by 12 for cubic feet. One BF is about 0.00236 m³, so 1,000 BF is about 2.36 m³.
What does 4/4 or 8/4 mean for hardwood?
Rough thickness in quarter inches: 4/4 is 1 in, 5/4 is 1¼ in and 8/4 is 2 in before planing. Board feet use the rough thickness.
What is the difference between the Doyle and Scribner log rules?
Both estimate lumber from a log. Doyle gives low figures for small logs and is common in the eastern and southern US. Scribner reads higher for small and medium logs and is common in the West.
What this calculator assumes
- Lumber uses the dimensions you enter. Use nominal sizes for softwood and rough sizes for hardwood.
- The Scribner figure uses the common Scribner Decimal C approximation formula. Official scale tables are rounded and may differ slightly.
- Prices are your entries and exclude tax and delivery.