Stax

…

Tools

Board Foot Calculator: Lumber Volume & Cost

Calculate board feet from thickness, width and length, with quantity, waste and cost. Converts to cubic feet and cubic metres.

Last updated:

Quick sizes (fills thickness and width of the last row)
—

Was this tool useful?

Use the tool above and you can rate it here.

What a board foot is

A board foot is a unit of lumber volume: 144 cubic inches, the volume of a board 1 inch thick, 12 inches wide and 1 foot long. It lets you price and compare boards of different sizes on one scale. With thickness and width in inches and length in feet, board feet = thickness × width × length ÷ 12. A 2×6 that is 12 feet long is 2 × 6 × 12 ÷ 12 = 12 board feet.

Board feet per piece at nominal sizes

Size (in)8 ft10 ft12 ft16 ft
1×42.673.334.005.33
1×64.005.006.008.00
1×85.336.678.0010.67
2×45.336.678.0010.67
2×68.0010.0012.0016.00
2×810.6713.3316.0021.33
2×1013.3316.6720.0026.67
2×1216.0020.0024.0032.00
4×410.6713.3316.0021.33

Nominal or actual size?

Use the dimensions your seller prices by. Softwood dimension lumber is sold by nominal size, but a dry, dressed 2×4 measures about 1½ by 3½ inches. Hardwood is usually priced by its rough thickness in quarters of an inch, where 4/4 means 1 inch. The calculator multiplies the numbers you enter, so you can run a job both ways and compare.

Waste, cost and conversions

Add an allowance for defects and trimming; the calculator starts at 10% and you can change it. Cost is the board feet to buy times the price per board foot: 72 board feet plus 10% waste is 79.2 board feet, which at $4.50 comes to $356.40. Twelve board feet make one cubic foot, so 72 board feet is 6 cubic feet. One board foot is 0.002359737 cubic metres. For paint, concrete and rebar quantities see the paint calculator, concrete volume calculator and rebar calculator.

Frequently asked questions

What is a board foot?
A board foot is a unit of lumber volume equal to 144 cubic inches, the volume of a board 1 inch thick, 12 inches wide and 1 foot long. With thickness and width in inches and length in feet, board feet = thickness × width × length ÷ 12. A 2×6 that is 12 feet long is 2 × 6 × 12 ÷ 12 = 12 board feet.
How many board feet are in a 2×4×8?
5.33 board feet, using the nominal size: 2 × 4 × 8 ÷ 12. Ten of them are 53.33 board feet. Pricing by the board foot is common for hardwood and for specialty lumber, while construction lumber is usually priced per piece.
Should I use nominal or actual dimensions?
Use the dimensions your seller prices by. Softwood dimension lumber is sold by nominal size, but a dry, dressed 2×4 measures about 1½ by 3½ inches. Hardwood is usually sold by its rough thickness in quarters (4/4 is 1 inch). The calculator multiplies whatever you enter, so you can run it both ways and compare.
How much extra lumber should I buy for waste?
There is no fixed figure; it depends on defects, the cut list and how much you trim. The calculator starts at 10% as a default and lets you change it. For 72 board feet, a 10% allowance means buying 79.2 board feet.
How do I convert board feet to cubic feet or cubic metres?
Twelve board feet make one cubic foot, so 72 board feet is 6 cubic feet. One board foot is 0.002359737 cubic metres (144 cubic inches), so 72 board feet is about 0.1699 cubic metres.
How do I work out the cost?
Multiply the board feet to buy (including waste) by the price per board foot. For 72 board feet plus 10% waste at $4.50 a board foot: 79.2 × $4.50 = $356.40.

Related tools