Board Foot Calculator
Calculate board feet from thickness, width, length, and board count. Includes waste allowance and cost estimate at your price per board foot.
Added Jun 16, 2026
Input
Result
Enter a value for thickness to see your result.
How it works
Calculates lumber volume in board feet from thickness, width, length, and board count. Optionally includes a waste allowance and total cost at your price-per-board-foot. One board foot equals 144 cubic inches of wood.
Formula
Board Feet = (Thickness × Width × Length in feet) ÷ 12
- Thickness
- Nominal thickness in inches (e.g. 1" for standard dimensional lumber)
- Width
- Nominal width in inches (e.g. 6" for a 1×6 board)
- Length
- Board length in feet
- ÷ 12
- Converts the inch×inch×foot product to board feet (1 BF = 144 in³)
Step by step
- 01Enter thickness and width in inches and length in feet.
- 02Enter the number of boards for your project.
- 03The calculator multiplies thickness × width × length (ft) and divides by 12 to get board feet per board.
- 04Multiply by board count for the total board feet.
- 05Add a waste percentage (typically 10–20%) for cutoffs and defects.
- 06If you enter a price per board foot, the total cost is also calculated.
Examples
10 boards of 1" × 6" × 8ft at $4.50/bf
A 1×6×8 board contains 4 board feet (1 × 6 × 8 ÷ 12). Ten boards = 40 BF. With 15% waste = 46 BF. At $4.50/BF the base cost is $180, with waste $207.
Inputs
- Thickness:
- 1
- Width:
- 6
- Length:
- 8
- Number of boards:
- 10
- Price per board foot (optional):
- 4.5
- Waste / cutoff allowance:
- 15
Result
- Total board feet:
- 40
- Board feet per board:
- 4
Frequently asked questions
What is a board foot?
A board foot (BF) is a unit of lumber volume equal to 144 cubic inches — the volume of a board 1 inch thick, 12 inches wide, and 12 inches long (1" × 12" × 12" = 144 in³). It is the standard unit for pricing hardwood lumber. Softwood dimensional lumber (2×4s, 2×6s) is often sold by the linear foot instead.
How do I calculate board feet?
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. Example: a 1" × 6" × 8ft board = (1 × 6 × 8) ÷ 12 = 4 board feet. For multiple boards, multiply by the board count.
Do I use nominal or actual dimensions?
Use nominal dimensions for board foot calculations when buying from a lumber yard — that's how they price it. A nominal 1×6 is actually 0.75" × 5.5", but lumber yards charge by the nominal 1×6 board foot measurement. Use actual dimensions only when calculating material needed for a project (cutting lists).
How much waste should I add?
Add 10–15% for clean, clear dimensional lumber with minimal knots. Add 15–20% for knotty or lower-grade lumber. Add 20–25% for reclaimed, rough-sawn, or character-grade hardwoods with more defects. The waste allowance covers end splits, knots in critical positions, and cutting errors.