Lumber Calculator
Hardwood is often priced by the board foot. Enter the board size and how many you need.
Use nominal sizes for priced lumber (a 2×6 is sold as 2 × 6 even though it measures 1.5 × 5.5 in).
Board feet and nominal sizes
Lumber is sold by nominal size, which is larger than the actual size. A 2×4 is really 1.5 × 3.5 inches, and a 2×6 is 1.5 × 5.5 inches. Board feet, used for hardwood pricing, are calculated from the nominal size: thickness × width (inches) × length (feet) ÷ 12.
Add 10–15% for cuts, defects and mistakes, and buy lengths that fit your cuts so you don't waste short offcuts.
Board feet in common lumber sizes
| Size | 8 ft | 10 ft | 12 ft | 16 ft |
|---|---|---|---|---|
| 1×4 | 2.67 | 3.33 | 4 | 5.33 |
| 1×6 | 4 | 5 | 6 | 8 |
| 1×8 | 5.33 | 6.67 | 8 | 10.67 |
| 2×4 | 5.33 | 6.67 | 8 | 10.67 |
| 2×6 | 8 | 10 | 12 | 16 |
| 2×8 | 10.67 | 13.33 | 16 | 21.33 |
| 2×10 | 13.33 | 16.67 | 20 | 26.67 |
| 2×12 | 16 | 20 | 24 | 32 |
| 4×4 | 10.67 | 13.33 | 16 | 21.33 |
| 6×6 | 24 | 30 | 36 | 48 |
Board feet = thickness (in) × width (in) × length (ft) ÷ 12
Building a fence? The fence calculator counts posts, rails and pickets.
Questions
What is a board foot?
A volume of wood 12 × 12 × 1 inches (144 cubic inches).
How many board feet in a 2×4×8?
5.33 board feet (2 × 4 × 8 ÷ 12).