Board foot calculator
Calculate board feet for lumber purchases, with support for multiple piece sizes and waste.
Board foot calculator
Calculate board feet for lumber purchases, with support for multiple piece sizes and waste.
Add your lumber pieces to see the board foot estimate.
Board feet needed
Project summary
How it works
These are volume estimates for planning. Actual lumber requirements depend on availability, grading and cutting waste.
Board foot calculator
What a board foot actually is
A board foot is a volume measure equal to one inch thick, one foot wide, and one foot long, or 144 cubic inches. Lumberyards and mills price hardwoods and some softwoods by the board foot because it accounts for the actual volume of wood rather than just the length. The formula is simple: thickness in inches times width in inches times length in feet, divided by 12.
Common lumber dimensions
A standard 2x4 is actually 1.5 by 3.5 inches, and a 1x6 is 0.75 by 5.5 inches. These are surfaced dimensions, meaning the lumber has been planed smooth from its rough-sawn size. If you are buying rough-sawn lumber, the dimensions are closer to the nominal name. The calculator uses the actual measurements you enter, so use the real dimensions, not the nominal ones.
Why waste matters for lumber
Wood has knots, checks, splits and grain direction that force you to cut around defects. Boards come in fixed lengths, so a 10-foot board used for an 8-foot run wastes 2 feet. A 10 to 15 percent waste allowance is common for hardwood, and 10 percent is typical for construction lumber where defects are fewer and cuts are simpler.
Frequently asked questions
How do you calculate board feet?
Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. For example, a board that is 1 inch thick, 6 inches wide, and 8 feet long is (1 x 6 x 8) / 12 = 4 board feet. For multiple identical pieces, multiply by the quantity.
What is the difference between board feet and linear feet?
Linear feet measures length only: a 10-foot board is 10 linear feet regardless of its width or thickness. Board feet measures volume: a 10-foot board that is 1 inch thick and 12 inches wide is 10 board feet, but a 10-foot board that is 1 inch thick and 6 inches wide is only 5 board feet.
How do I calculate board feet?
Board feet equals thickness in inches multiplied by width in inches multiplied by length in feet, divided by 12. A board that is 2 inches thick, 6 inches wide and 10 feet long is 10 board feet. The calculator does this automatically.
How much does a board foot of hardwood cost?
Hardwood prices range from 3 to 20 dollars per board foot depending on species. Common species like oak cost 4 to 8 dollars. Exotic species cost more. The calculator gives you the total board feet so you can price your project.
How do I convert board feet to cubic feet?
Divide board feet by 12 to get cubic feet. 100 board feet equals 8.33 cubic feet. The calculator shows both measurements.
Why do lumber yards sell by board feet?
Board feet accounts for the actual volume of wood, which varies with thickness and width. A 2 by 6 has more wood than a 2 by 4 of the same length. Pricing by board feet gives a fair comparison. The calculator helps you estimate total board feet for your project.
How much waste should I add for hardwood?
Hardwood waste depends on the project. Cutting for furniture typically needs 20 to 30 percent. Simple dimension lumber needs less. The calculator lets you set the waste percentage.
How many board feet are in a 2x4x8?
A standard 2x4 that is 8 feet long contains 5.33 board feet, calculated as 2 times 4 times 8 divided by 12. However, a surfaced 2x4 actually measures 1.5 by 3.5 inches, which gives 3.5 board feet. The calculator uses the actual measurements you enter, so use the real dimensions rather than the nominal ones for an accurate count.