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Board Foot Calculator

Enter a board’s thickness and width in inches and its length in feet to get board feet, the unit hardwood and rough lumber are sold in. Add the number of boards and a price per board foot for the total cost.

Quick examples

Hardwood is sold by its rough (nominal) thickness: 4/4 = 1 in, 8/4 = 2 in.

$
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Total board feet80 BF
Board feet per board
8 BF
Total cost
$360.00
Cost per board
$36.00

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      Formula

      Board feet = thickness (in) × width (in) × length (ft) ÷ 12
      Total board feet = board feet per board × number of boards
      Cost = total board feet × price per board foot

      How to use it

      1. Enter the thickness and width in inches.
      2. Enter the length in feet.
      3. Enter how many boards of that size you need.
      4. Enter the price per board foot to get the cost.

      Worked examples

      Ten boards 2 in thick, 6 in wide and 8 ft long at $4.50 a board foot

      Board feet per board
      8 BF
      Total board feet
      80 BF
      Total cost
      $360.00
      Cost per board
      $36.00

      Five 1 in × 8 in boards, 10 ft long, at $6 a board foot

      Board feet per board
      6.67 BF
      Total board feet
      33.33 BF
      Total cost
      $200.00
      Cost per board
      $40.00

      What a board foot is

      One board foot is a volume of 144 cubic inches: a board 1 in thick, 12 in wide and 12 in long. With all three measurements in inches, divide by 144 instead of 12.

      Hardwood dealers quote thickness in quarters of an inch: 4/4 is 1 in, 5/4 is 1¼ in, 6/4 is 1½ in and 8/4 is 2 in. Board footage is calculated on that rough thickness, even if the board has since been planed thinner.

      Nominal versus actual sizes

      Softwood framing lumber is named by nominal size — a 2×6 actually measures 1½ × 5½ in — and when it is sold by the board foot the nominal dimensions are used. So a 2×6 that is 8 ft long counts as 8 board feet.

      When buying rough hardwood for a project, add 20–30% to your finished parts list to cover defects, planing and offcuts.

      Questions people ask

      How do you calculate board feet?

      Multiply thickness in inches by width in inches by length in feet, then divide by 12. A 2 in × 6 in × 8 ft board is 2 × 6 × 8 ÷ 12 = 8 board feet.

      How many board feet are in a 2×4×8?

      5.33 board feet: 2 × 4 × 8 ÷ 12.

      How many board feet are in a 1×6 that is 10 ft long?

      5 board feet: 1 × 6 × 10 ÷ 12.

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