Lumber Calculator for Construction Takeoffs
Accurate lumber calculations are essential for framing, sheathing, and construction projects. Our free lumber calculator helps contractors calculate board footage, linear footage, and costs while accounting for nominal vs. actual dimensions and waste factors.
Understanding Board Footage
Board footage standardizes lumber pricing regardless of size:
- Formula: (Thickness × Width × Length) ÷ 144
- Measurements: All in inches
- Example: 2×4×8 = (2 × 4 × 96) ÷ 144 = 5.33 board feet
- Use: Pricing, estimating, and material ordering
Nominal vs. Actual Dimensions
Lumber is sold by nominal size but has smaller actual dimensions:
- 2×4: Nominal 2"×4", Actual 1.5"×3.5"
- 2×6: Nominal 2"×6", Actual 1.5"×5.5"
- 2×8: Nominal 2"×8", Actual 1.5"×7.25"
- 2×10: Nominal 2"×10", Actual 1.5"×9.25"
- 2×12: Nominal 2"×12", Actual 1.5"×11.25"
Lumber Grades and Applications
Choose the right grade for your application:
- Stud Grade (#2): General framing, economical
- Select Structural: Higher strength, load-bearing
- Premium: Clear, appearance grade
- Pressure Treated: Outdoor use, rot resistant
- Engineered: I-joists, laminated veneer lumber (LVL)
Framing Material Calculations
Standard framing requirements:
- Wall Studs: 16" on center spacing
- Top/Bottom Plates: Full wall length
- Headers: Double or laminated for openings
- Rafters/Trusses: 16-24" on center
- Bridging/Blocking: For stability
Sheathing Calculations
Plywood and OSB for roofs, walls, and floors:
- Roof Sheathing: 4×8 sheets, 32 sq ft each
- Wall Sheathing: 4×8 or 4×9 sheets
- Floor Sheathing: 4×8 sheets, tongue and groove
- Stagger Joints: For strength and stability
- Overhang: Add for eaves and rakes
Lumber Waste Factors
Always account for waste in your calculations:
- Framing Lumber: 10-15% waste for cuts
- Sheathing: 5-10% waste for patterns
- Long Lengths: More waste from shorter pieces
- Complex Framing: Higher waste factor
- Future Use: Keep scraps for blocking