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Board Foot Calculator

Board feet and cost for any stack of lumber: hardwood sold in quarters or construction lumber like 2 × 4s.

Each board
in
Hardwood is sold in quarters: 4/4 = 1 in, 5/4 = 1.25 in, 6/4 = 1.5 in, 8/4 = 2 in. For construction lumber, use the size it's sold as (a 2 × 4 is 2 in).
Your price
Your price
$
Leave at 0 to skip the cost estimate.
Total 40 board feet 4 board feet per board × 10 boards, 80 linear ft in total.

Details

Per board
4 board ft
Linear feet
80 ft
Cubic feet
3.33 cu ft

Cost

How do I calculate board feet?

Multiply thickness (in) × width (in) × length (ft), then divide by 12. One board foot is 144 cubic inches, the same as a board 1 inch thick, 12 inches wide and 1 foot long. A 1 × 6 board 8 ft long is 1 × 6 × 8 ÷ 12 = 4 board feet, so 10 of them are 40 board feet.

Worked example: ten 1 × 6 boards, 8 ft long

  1. One board: 1 in × 6 in × 8 ft ÷ 12 = 4 board feet.
  2. All boards: 4 × 10 = 40 board feet.
  3. Cost: at, say, $6 per board foot, that's $240. Enter your yard's price to see yours.

If the length is in inches instead, divide by 144 instead of 12: 1 × 6 × 96 ÷ 144 = 4 board feet.

Board feet per linear foot

Multiply by the length in feet to get board feet for one board.

Size (thickness × width)Board feet per foot of length
1 × 40.33
1 × 60.50
1 × 80.67
1 × 121.00
2 × 40.67
2 × 61.00
2 × 81.33
2 × 101.67
2 × 122.00
4 × 41.33

Thickness × width ÷ 12. For example, a 2 × 6 that is 10 ft long is 1.00 × 10 = 10 board feet.

Quarters: 4/4, 5/4, 8/4

Hardwood lumber is sold by thickness in quarter inches, measured when the board is rough-sawn:

  • 4/4 ("four quarter") = 1 in
  • 5/4 = 1¼ in
  • 6/4 = 1½ in
  • 8/4 = 2 in

Enter the quarter size as inches (for 5/4, enter 1.25). The board gets thinner once it is planed, but it is priced by its rough thickness.

Nominal vs actual size

Construction lumber has a nominal size (the name, such as 2 × 4) and a smaller actual size after drying and planing (about 1½ × 3½ in). Lumber yards price board feet by the size they sell it as, so enter the nominal size. Use the actual measurements only if you are working out the real volume of wood, for example for weight.

Frequently asked questions

What is a board foot?
A unit of lumber volume equal to 144 cubic inches: a piece 1 inch thick, 12 inches wide and 12 inches long, or any board with the same volume.
How many board feet is a 2 × 4 × 8?
5.33 board feet: 2 × 4 × 8 ÷ 12.
How many board feet is a 2 × 6 × 10?
10 board feet: 2 × 6 × 10 ÷ 12.
How do I calculate board feet with the length in inches?
Multiply thickness × width × length, all in inches, and divide by 144.
How do I convert board feet to cubic feet?
Divide by 12. There are 12 board feet in a cubic foot, because 12 × 144 = 1,728 cubic inches.

Guides

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Sources and method

Last checked October 12, 2026. How we build and test every calculator: methodology.