Board Foot Calculator
Enter the thickness, width, length and quantity of each board to get the total board feet — the unit lumberyards and hardwood dealers use to price wood — and what your order will cost.
Enter the size and number of your boards.
On this page
What is a board foot?
A board foot is a volume of wood equal to a board 1 inch thick, 12 inches wide and 1 foot long — 144 cubic inches. Lumberyards and hardwood dealers price wood by the board foot because it lets them compare boards of any size: a 2-inch-thick board 6 inches wide holds exactly as much wood per foot as a 1-inch board 12 inches wide.
How to calculate board feet
Worked example: ten 2×6 boards, 8 ft long
- One board: 2 × 6 × 8 ÷ 12 = 8 board feet
- Ten boards: 80 board feet
Worked example: one 8/4 walnut board, 7 in wide and 6 ft long, at $12 per board foot
- 8/4 means 8 quarters of an inch, so 2 inches thick
- 2 × 7 × 6 ÷ 12 = 7 board feet, costing 7 × $12 = $84
Board feet for common lumber sizes
| Nominal size | Per foot of length | 8 ft board | 12 ft board |
|---|---|---|---|
| 1×4 | 0.33 bf | 2.67 bf | 4 bf |
| 1×6 | 0.5 bf | 4 bf | 6 bf |
| 1×8 | 0.67 bf | 5.33 bf | 8 bf |
| 2×4 | 0.67 bf | 5.33 bf | 8 bf |
| 2×6 | 1 bf | 8 bf | 12 bf |
| 2×8 | 1.33 bf | 10.67 bf | 16 bf |
| 2×10 | 1.67 bf | 13.33 bf | 20 bf |
| 2×12 | 2 bf | 16 bf | 24 bf |
| 4×4 | 1.33 bf | 10.67 bf | 16 bf |
| 6×6 | 3 bf | 24 bf | 36 bf |
Nominal or actual size?
Construction lumber is sold by its nominal size: a 2×4 actually measures about 1½ × 3½ inches after drying and planing. Dimensional softwood lumber is usually priced using the nominal size, so a 2×4 counts as 2 × 4 inches. Hardwood dealers work differently: they measure rough-sawn boards by thickness in quarters of an inch and by their actual width and length.
| Hardwood thickness | Rough thickness |
|---|---|
| 4/4 ("four quarter") | 1 in |
| 5/4 | 1¼ in |
| 6/4 | 1½ in |
| 8/4 | 2 in |
| 12/4 | 3 in |
If you're comparing prices between a lumberyard and a hardwood dealer, or buying surfaced boards, ask which measurement the price is based on — it can change the board-foot count noticeably.
Frequently asked questions
How many board feet are in a 2×4×8?
2 × 4 × 8 ÷ 12 = 5⅓ board feet, using the nominal size.
Is a board foot the same as a linear foot?
No. A linear foot is just length, whatever the size of the board. A board foot is a volume, so a foot of 2×12 is 2 board feet while a foot of 1×4 is a third of a board foot.
How many board feet in a cubic foot?
12. A cubic foot is 1,728 cubic inches, and a board foot is 144 cubic inches.
What is a board foot in metric?
One board foot is about 2.36 liters, or 0.00236 cubic meters. A cubic meter is about 424 board feet.
Sources
- American Softwood Lumber Standard (NIST Voluntary Product Standard PS 20) — nominal and actual sizes of softwood lumber.
- National Hardwood Lumber Association (NHLA) rules — thickness in quarters and board-foot measure for hardwood lumber.
- How we calculate.