Board feet only apply to hardwood and rough lumber — construction softwood like 2×4s is sold by the piece or by linear foot, so you'll rarely need this at a big-box store. At a hardwood dealer, expect prices from roughly $3–$6 per board foot for domestic species like poplar, oak and maple, up to $15–$30+ for walnut and exotics. Add 15–30% waste allowance for defects, checking and milling loss when ordering for a project; the quantity field makes it easy to price the padded number.
Board Foot Calculator
Board feet per board and for the whole stack — priced instantly at your per-board-foot rate.
Board dimensions
Hardwood dealers quote nominal (rough) sizes — use those, e.g. 4/4 = 1″ thick.
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What is a board foot?
A board foot is the standard volume unit for hardwood lumber: 1 board foot = 144 cubic inches — a piece 1″ thick × 12″ wide × 1 ft long. The formula is:
Board feet = (thickness in × width in × length ft) ÷ 12
So an 8-ft 1×6 contains (1 × 6 × 8) ÷ 12 = 4 board feet.
Nominal sizes and quarter notation
Hardwood is priced on nominal (rough-sawn) dimensions, quoted in quarters of an inch of thickness: 4/4 (“four-quarter”) = 1″, 5/4 = 1¼″, 8/4 = 2″. Even after surfacing a 4/4 board to ¾″, you still pay for the full inch — always enter nominal sizes here to match the dealer's invoice.
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Frequently asked questions
How do you calculate board feet?
Multiply thickness (inches) × width (inches) × length (feet) and divide by 12. An 8-ft-long 1×6 is (1 × 6 × 8) ÷ 12 = 4 board feet.
Is a board foot the same as a linear foot?
No. A linear foot measures length only, ignoring width and thickness. A board foot measures volume — 144 cubic inches — so wider or thicker boards contain more board feet per linear foot.
What does 4/4, 5/4 or 8/4 lumber mean?
Hardwood thickness is quoted in quarter inches: 4/4 = 1″, 5/4 = 1¼″, 6/4 = 1½″, 8/4 = 2″. These are rough-sawn nominal thicknesses — the surfaced board is thinner but priced at the nominal size.
Do I use nominal or actual dimensions?
Use nominal (rough) dimensions — that's what dealers charge on. A surfaced 4/4 board measures about ¾″ but is still billed as 1″ thick.