Board Feet Calculator
Calculate hardwood lumber volume in board feet (BF), estimate waste margins, and calculate total job cost based on board price.
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What is a Board Foot?
A board foot (abbreviated BF or FBM for Foot Board Measure) is a specialized unit of volume used in the North American lumber industry. One board foot represents a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches (1 foot) long, totaling 144 cubic inches.
Length in Feet
BF = (Thick" × Width" × Length') / 12
Length in Inches
BF = (Thick" × Width" × Length") / 144
Understanding Quarter System Thickness
Hardwood sawmills sell rough-cut lumber in fractions of an inch expressed in quarters:
- 4/4 (Four-Quarter): 1 inch thick rough (surfaces to ~3/4")
- 5/4 (Five-Quarter): 1-1/4 inch thick rough (surfaces to ~1")
- 6/4 (Six-Quarter): 1-1/2 inch thick rough (surfaces to ~1-1/4")
- 8/4 (Eight-Quarter): 2 inches thick rough (surfaces to ~1-3/4")
Frequently Asked Questions
Why is board foot different from linear foot and square foot?
Linear feet only measures length along one axis. Square feet measures surface area (length x width) regardless of depth. Board feet measures three-dimensional physical volume (thickness x width x length).
Why should I add 15% waste to hardwood lumber orders?
Rough-sawn hardwood boards often contain natural defects like checks, end splits, knots, sapwood, and warp. Jointing and planing boards flat removes material, so adding 15% to 20% ensures you have enough usable yield.
What does MBF mean on lumber quotes?
MBF stands for Thousand Board Feet (the "M" is Roman numeral for 1,000). A quote of $4,500/MBF translates to $4.50 per individual board foot.