Free Woodworking Board Foot Calculator
Calculate exact board feet (BF) volume, account for rough milling scrap waste, and estimate total hardwood lumber project cost.
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📊 Total Board Footage & Cost
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How Board Footage is Calculated
Unlike softwood dimensional construction lumber (2x4s sold by the piece), hardwood lumber is sold strictly by volume in Board Feet (BF). One board foot is defined as a nominal piece of lumber 1 inch thick, 12 inches wide, and 1 foot (12 inches) long, equaling 144 cubic inches.
The Board Foot Formulas
Understanding the Quarter System (4/4, 8/4)
Hardwood sawmills measure thickness in quarters of an inch: 4/4 ("four-quarter") is 1.00" thick rough (finishes to ~3/4" or 13/16"), 5/4 ("five-quarter") is 1.25" rough (finishes to 1.00"), 6/4 ("six-quarter") is 1.50" rough (finishes to 1.25"), and 8/4 ("eight-quarter") is 2.00" rough (finishes to 1.75"). Always calculate board footage using the nominal rough thickness you purchase, not the final planed thickness.
Frequently Asked Questions
Why do I need to add 15% to 20% waste for hardwoods?
Rough lumber has natural defects including checking (cracks at board ends), cupping, twisting, sapwood edges, and planer snipe. Squaring edges on a jointer and trimming checked ends naturally removes 15% to 20% of the purchased volume.
What is the difference between BF and Linear Feet?
Linear footage measures only length along the board regardless of width or thickness. A 10-foot long board that is 12 inches wide contains 10 board feet (at 4/4 thickness), whereas a 10-foot long board that is only 3 inches wide contains only 2.5 board feet.
If my finished board is 0.75" thick, do I pay for 4/4?
Yes. To produce a finished 3/4" (0.75") thick planed board, you must buy rough 4/4 (1.00") stock. Hardwood lumber yards charge for the 1.00" rough thickness required to mill it.