Lumber calculator
Board feet calculator
Calculate board feet for dimensional lumber and hardwood. Enter thickness, width, length, and quantity to get the total board feet.
Lumber calculator
Lumber calculator result
Common lumber sizes
Nominal vs. actual lumber dimensions (actual is what the calculator uses):
- 2x4: 1.5 x 3.5 inches actual
- 2x6: 1.5 x 5.5 inches actual
- 2x8: 1.5 x 7.25 inches actual
- 2x10: 1.5 x 9.25 inches actual
- 4x4: 3.5 x 3.5 inches actual
- 1x6: 0.75 x 5.5 inches actual
Worked example
For example, for ten 2×6 boards, 8 ft long:
- Board feet = (2 × 6 × 8) ÷ 12 = 8 bd ft per board
- Total for 10 boards = 8 × 10 = 80 bd ft
- Actual dimensions: 1.5 × 5.5 in (nominal 2×6)
- Buy 11 boards to account for defects and offcuts
- Check each board for warping, twisting, or excessive knots before buying
Common mistakes
| Mistake | Why it matters |
|---|---|
| Confusing nominal vs actual dimensions | A 2×4 is actually 1.5 × 3.5 in — always use actual dimensions for calculations |
| Not accounting for waste | Plan for 10-15% waste from cutting, defects, and unusable sections |
| Buying pressure-treated for indoor use | PT lumber contains chemicals — use kiln-dried lumber for interior projects |