Nominal vs actual lumber sizes
What a 2×4 really measures.
Dimensional lumber is named by its rough size before drying and planing, so the finished board is smaller. These are the usual actual sizes for common US softwood boards. Sizes can vary slightly, so measure the boards you buy.
| Nominal | Actual (thickness × width) |
|---|---|
| 1×4 | 3/4" × 3 1/2" |
| 1×6 | 3/4" × 5 1/2" |
| 1×8 | 3/4" × 7 1/4" |
| 1×12 | 3/4" × 11 1/4" |
| 2×4 | 1 1/2" × 3 1/2" |
| 2×6 | 1 1/2" × 5 1/2" |
| 2×8 | 1 1/2" × 7 1/4" |
| 2×10 | 1 1/2" × 9 1/4" |
| 2×12 | 1 1/2" × 11 1/4" |
| 4×4 | 3 1/2" × 3 1/2" |
Figuring volume or cost? Try the board feet calculator.