Construction

Lumber Cost Calculator

Enter your board dimensions, quantity, and price per board foot to calculate total board feet and total lumber cost for a project.

Board dimensions

in
in
ft
$
Total cost
Enter your board details to calculate.

How the Lumber Cost formula works

Board feet, then converted to cost:

Board feet per piece = (Thickness in × Width in × Length ft) / 12
Total cost = Board feet per piece × Quantity × Price per board foot

Step-by-step calculation

  1. Multiply a board's thickness and width in inches by its length in feet.
  2. Divide by 12 to get board feet for one piece.
  3. Multiply by the number of pieces and by the price per board foot.

Worked example

10 boards, each 2 in thick, 6 in wide, 8 ft long, at $4.50 per board foot: Board feet per piece = (2×6×8)/12 = 8. Total board feet = 8×10 = 80. Total cost = 80 × 4.50 = $360.

Frequently asked questions

What's a 'board foot' exactly?

A board foot is a unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches) — it's the standard unit lumber is priced by, rather than a simple linear foot.

Does this include waste allowance for cuts?

No — this calculates exact board footage for the given dimensions and quantity. Add extra pieces or a percentage buffer separately to account for cutting waste and mistakes.