Lumber Calculator
Calculate lumber board feet and volume
Table of Contents
How to Use
- Enter lumber thickness in inches
- Enter lumber width in inches
- Enter lumber length in feet
- Enter quantity of boards
- Click calculate to get board feet, volume, and weight
Understanding Lumber Calculations
Lumber calculations involve measuring volume in both board feet and cubic feet. Board feet is the standard unit for pricing lumber, while cubic feet helps estimate weight and storage requirements.
Board Feet Formula
Board Feet = (Thickness × Width × Length) ÷ 144
All measurements must be in inches, except length which is in feet.
Cubic Feet Formula
Cubic Feet = (Thickness × Width × Length) ÷ 1,728
Useful for calculating weight and storage space.
Weight Estimation
Weight is estimated using average softwood density of 30 lbs/ft³. Actual weight varies by species and moisture content.
- Softwoods (pine, fir): 25-35 lbs/ft³
- Hardwoods (oak, maple): 40-60 lbs/ft³
- Moisture adds 20-50% weight to green lumber
Frequently Asked Questions
- What's the difference between board feet and cubic feet?
- Board feet is a specialized lumber measurement (12" × 12" × 1" = 1 board foot) used for pricing. Cubic feet is standard volume measurement (12" × 12" × 12" = 1 cubic foot) used for weight and storage calculations.
- How accurate is the weight estimate?
- Weight estimates assume average softwood density (30 lbs/ft³). Actual weight varies significantly: hardwoods are heavier (40-60 lbs/ft³), and moisture content can add 20-50% more weight.
- Do I need to account for waste?
- Yes, always add 10-20% extra for waste, defects, and cutting errors. Complex projects may require more.
- Can I use actual dimensions instead of nominal sizes?
- Yes, this calculator uses the exact dimensions you enter. For standard lumber, remember that nominal sizes differ from actual (e.g., a 2×4 actually measures 1.5" × 3.5").
- How do I calculate for different length boards?
- Calculate each length separately, then add the totals together for your complete project requirements.