Lumber Dimensions
Lumber is sold by nominal size but is actually smaller after milling:
- 2×4 → actual 1.5" × 3.5" (38 × 89 mm)
- 2×6 → actual 1.5" × 5.5" (38 × 140 mm)
- 1×4 → actual 0.75" × 3.5" (19 × 89 mm)
Essential Carpentry Math
- Board foot: 1" × 12" × 12" (144 cubic inches)
- Linear foot: 12 inches of length at any width
- Rise and run: For stairs, typical 7" rise and 10" run