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.
By Utilix Editorial Team · 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.