Board Foot Calculator
Calculate board feet (BF) lumber volume, estimate total board quantities, and calculate material pricing for woodworking, sawmills, and construction.
| Net Volume (10 boards) | 40.00 BF |
| Waste Allowance Buffer | +6.00 BF (15%) |
| Cubic Volume Equivalent | 3.83 Cubic Feet (0.14 cu yd) |
| Linear Length Total | 80.0 Linear Feet |
What is a Board Foot (BF / FBM)?
A Board Foot (often abbreviated as BF or FBM for Foot Board Measure) is a specialized unit of measurement used in the lumber, timber, and woodworking industries.
One board foot represents the volume of a board that is 1 inch thick, 12 inches wide, and 12 inches (1 foot) long. This equals exactly 144 cubic inches of wood.
The Mathematics of Board Foot Volume
Here are the standard mathematical formulas used by sawmills and lumber yards:
Board Feet = (Thickness in inches * Width in inches * Length in feet) / 12
Formula 2 (Length in Inches):
Board Feet = (Thickness in inches * Width in inches * Length in inches) / 144
Total Project Board Feet = (Board Feet per piece * Quantity) * (1 + Waste % / 100)
Total Lumber Cost ($) = Total Project Board Feet * Price per Board Foot ($/BF)
Cubic Feet Equivalent = Total Board Feet / 12
Step-by-Step Worked Calculation Example
Suppose you need 10 pieces of 1" thick by 6" wide by 8' long boards at $6.50 per board foot with 15% waste:
- Board feet per board:
(1 inch * 6 inches * 8 feet) / 12 = 4.0 BF per board. - Net board feet for 10 boards:
4.0 BF * 10 = 40.0 BF. - Add 15% waste buffer:
40.0 BF * 1.15 = 46.0 BF. - Calculate total cost:
46.0 BF * $6.50 = $299.00.
Master Dimensional Lumber Board Foot Reference Table
Look up nominal lumber sizes to find board feet per single board across common lengths:
| Nominal Board Size | 8-Foot Board | 10-Foot Board | 12-Foot Board | 14-Foot Board | 16-Foot Board |
|---|---|---|---|---|---|
| 1x4 | 2.67 BF | 3.33 BF | 4.00 BF | 4.67 BF | 5.33 BF |
| 1x6 (Our Default) | 4.00 BF | 5.00 BF | 6.00 BF | 7.00 BF | 8.00 BF |
| 1x8 | 5.33 BF | 6.67 BF | 8.00 BF | 9.33 BF | 10.67 BF |
| 2x4 (Stud) | 5.33 BF | 6.67 BF | 8.00 BF | 9.33 BF | 10.67 BF |
| 2x6 (Joist) | 8.00 BF | 10.00 BF | 12.00 BF | 14.00 BF | 16.00 BF |
| 2x8 (Rafter) | 10.67 BF | 13.33 BF | 16.00 BF | 18.67 BF | 21.33 BF |
| 2x10 (Floor Joist) | 13.33 BF | 16.67 BF | 20.00 BF | 23.33 BF | 26.67 BF |
| 2x12 (Stringer / Beam) | 16.00 BF | 20.00 BF | 24.00 BF | 28.00 BF | 32.00 BF |
The Hardwood Quarter-Sizing System Explained
Hardwood lumber yards sell rough-sawn lumber measured in fractions of an inch (quarters):
- 4/4 ("Four-Quarter"): 1.0 inch rough thickness (planes down to 3/4" S2S finished).
- 5/4 ("Five-Quarter"): 1.25 inches rough thickness (planes down to 1" S2S finished).
- 6/4 ("Six-Quarter"): 1.5 inches rough thickness (planes down to 1-1/4" S2S finished).
- 8/4 ("Eight-Quarter"): 2.0 inches rough thickness (planes down to 1-3/4" S2S finished).
- 12/4 ("Twelve-Quarter"): 3.0 inches rough thickness (planes down to 2-3/4" heavy slab).
5 Tips When Buying Lumber at Sawmills
Frequently Asked Questions
A board foot (abbreviated BF or FBM) is a specialized unit of lumber volume representing a piece of wood that is 1 inch thick, 12 inches wide, and 1 foot (12 inches) long, totaling 144 cubic inches.
Multiply thickness in inches by width in inches by length in inches, and divide the total by 144. Formula: BF = (T * W * L) / 144.
Linear feet measures only the one-dimensional length of a board regardless of width or thickness. Board feet measures three-dimensional volumetric wood content.
A nominal 2x4x8 board contains (2 * 4 * 8) / 12 = 5.33 Board Feet.
Softwood (pine, fir) is mass-produced in standardized dimensional lumber sizes (2x4, 2x6). Hardwoods (oak, walnut, maple) are milled in random widths and lengths from logs, making volumetric board foot pricing fairer.