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Lumber Board Feet Calculator

Enter thickness, width, length, and quantity for each board size to calculate total board feet and cost.

Thickness (in)Width (in)Length (ft)QtyBoard ft
40.00
40.00 board feet
≈ $180.00 at $4.50/board foot

Board feet = (thickness in × width in × length ft) ÷ 12, the standard lumber measurement formula. Actual dressed (surfaced) lumber is often slightly smaller than its nominal size — check your supplier's actual dimensions if pricing matters.

How to use this tool

  1. 1Enter thickness, width, and length for a board size.
  2. 2Enter the quantity of that size.
  3. 3Add more board sizes if needed.
  4. 4See total board feet and estimated cost.

Frequently asked questions

What's the board feet formula?+

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12 — the standard lumber industry measurement.