Understanding hardwood grades
No two hardwood boards look alike. That's why each hardwood board is assigned a grade at the mill by a lumber grader. Each grade, below, is based on a percentage of yield in clear face cuttings as seen from the clearest side of the board.
Easy board foot calculation
Hardwoods sell in grades by the board foot, a basic unit of measurement that equals a 1"-thick board that's 12" wide and 12" long. That's because hardwoods—unlike softwoods—aren't cut and milled as dressed, sized lumber in standard nominal dimensions (2X4, 1X6, 4X4, etc.) to only be cut to length for construction. Instead, mills saw hardwoods into random widths and lengths to best take advantage of the clear wood in a log. Hardwoods do come in nominal thicknesses, such as 1", 11⁄4 ", etc. (often referred to as four-quarter, five-quarter, and so on), that actually are a bit shy of the stated thickness. Therefore, you'll pay for a 1"-thick measurement but actually be getting about 3⁄16 " less. Board widths aren't standardized. Typically, the dealer will "round up" to the next inch of width and charge you for it. To help you in estimating stock and cost for the projects you want to build, the chart below gives you the amount of board feet in a range of common hardwood dimensions you'll likely come across where you shop for wood.
BOARD FOOT CALCULATOR