Calculate exactly how many board feet and the total cost of your lumber. Accounts for nominal vs actual dimensions and rough-to-finish waste.
In the hardwood lumber industry, wood is not sold by the linear foot; it is sold by the board foot. One board foot is a volume of wood measuring exactly 12 inches x 12 inches x 1 inch (144 cubic inches).
The Math: To calculate board feet, multiply the Thickness (in) x Width (in) x Length (ft) and divide by 12. Our calculator does this instantly, even if you are buying multiple boards of the same size.
This is the #1 point of confusion for beginners at the lumberyard. When you buy a "2x4" or a "1x6", those are the nominal (named) dimensions. The actual dimensions are smaller because the wood shrinks as it dries and is planed smooth at the mill.
Not all lumber is priced the same way. Knowing the difference will save you from looking confused at the supply store.
If you are buying "S4S" (Surfaced 4 Sides) lumber from a big box store, it is ready to use. But if you are buying "Rough Sawn" lumber from a hardwood dealer, it is thick, fuzzy, and uneven.
To get a smooth finish, you must run it through a jointer and a planer. This process removes 1/8" to 1/4" of material from every face. Our calculator includes a "Rough-to-Finish Waste Factor" (defaulted to 15%) to ensure you buy enough rough lumber to yield your final, finished dimensions.
Wood moves. It expands and contracts with humidity. If you build a table with wet wood, it will crack and warp when you bring it inside your climate-controlled home.
Woodworking projects vary wildly. Here is how to use our calculator for the most common scenarios.
Use the actual dimensions: 1.5" thick x 3.5" wide x 8 feet long. (1.5 x 3.5 x 8) / 12 = 3.5 board feet. However, softwood 2x4s are usually sold by the linear foot, not the board foot.
It means "four-quarter" or "eight-quarter". 4/4 is 1 inch thick (rough). 8/4 is 2 inches thick (rough). After planing, 4/4 becomes 3/4" thick, and 8/4 becomes 1.75" thick.
Hardwoods grow much slower than softwoods, taking decades to reach harvest size. They also require more energy to kiln-dry and more labor to process. The price reflects the density, beauty, and longevity of the wood.
Poplar or Soft Maple. They are relatively inexpensive, easy to work with hand or power tools, and take paint and stain very well. Avoid Oak or Walnut until you are comfortable with your tools, as mistakes are expensive!
Store it flat on a level surface, supported by stickers (small wooden spacers) every 12-18 inches to allow air to circulate. Keep it out of direct sunlight and extreme temperature changes.