Board Foot Calculator

Enter a board's thickness, width and length to get its volume in board feet. Add pieces to a cut list to total up an order and estimate cost.

Common Lumber Sizes
Softwood lumber is billed at its nominal size, so a 2×4 counts as 2″ × 4″.
$
Lumber yards often quote per board foot, mills and wholesalers per thousand board feet (MBF, where M is the Roman numeral for 1,000), and home centers per board.
Fractions work too: try 1 1/2, 3/4 or 5/4.
5.33
Board Feet
Per piece
5.33 BF
Thousand board feet
0.005 MBF
Cubic feet
0.444 ft³
Cubic meters
0.0126 m³
Cost
Add a price to estimate

Cut List

Pieces you add are saved in this browser.

QtySize (T × W × L)BF EachBF TotalPrice$/BFCost
No pieces yet. Enter a board above and choose Add to cut list.

How to Calculate Board Feet

A board foot is a unit of lumber volume equal to a piece 12 inches long, 12 inches wide and 1 inch thick, or 144 cubic inches. To find board feet, multiply the thickness and width in inches by the length in feet, then divide by 12.

Board feet = thickness (in) × width (in) × length (ft) ÷ 12

If you measure length in inches, divide by 144 instead. For example, a 2×6 that is 10 feet long is 2 × 6 × 10 ÷ 12 = 10 board feet. Ten of them would be 100 board feet.

Nominal vs. Actual Size

Dimensional softwood lumber is sold by its nominal size. A 2×4 actually measures about 1½″ × 3½″ after drying and planing, but board feet are calculated with 2″ × 4″. Hardwood is usually sold by the thickness of the rough-sawn board, stated in quarter inches: 4/4 is 1″, 5/4 is 1¼″, 8/4 is 2″. Surfaced hardwood is typically still priced on its rough thickness.

Common Lumber Sizes in Board Feet

Nominal Size8 ft10 ft12 ft16 ft

Tips for Ordering

Add a waste allowance for defects, end checks and offcuts. Around 10% is common for construction lumber, and 20% to 30% is typical for hardwood projects where you'll cut around knots and grain. Mills and wholesalers quote prices per thousand board feet, written as MBF or $/M. Divide by 1,000 to get the price per board foot: $850 per MBF is $0.85 per board foot. Choose Per MBF in the price options and the calculator converts it for you.

Home centers usually price each board rather than by volume. Switching the price type to per board shows the equivalent price per board foot, which makes it easy to compare a store's shelf price with a lumber yard quote.