How to use this calculator
- Choose US customary or metric dimensions.
- Enter actual thickness, width, length, and whole-piece quantity.
- Add differently sized lumber as separate entries.
- Calculate total board feet and supporting volume equivalents.
How the calculation works
Each lumber entry uses the standard board-foot relationship, then all entry totals are added. Metric dimensions are converted before the same physical-volume calculation.
Formula
Board feet = thickness (in) × width (in) × length (ft) × quantity ÷ 12 Total board feet = sum of all entries
Worked example
Ten boards measuring 2 in × 6 in × 8 ft contain `(2 × 6 × 8 × 10) ÷ 12 = 80` board feet. Their combined linear length is 80 ft and physical volume is about 6.67 cubic feet.
Project considerations
- Board feet measure volume, not square coverage or linear length.
- Use actual dimensions when an exact physical-volume result is needed.
- Price, grade, nominal-versus-actual conventions, and structural suitability are not calculated.
Frequently asked questions
Is one board foot one square foot?
No. A board foot is 144 cubic inches of lumber volume, conventionally equivalent to a 1 in × 12 in × 1 ft board.
Can I combine different board sizes?
Yes. Add every size and quantity as a separate lumber entry.