The standard measurement of lumber is board feet. According to the National Hardwood Lumber Association, one board foot is 12" wide by 12" long and 1" thick (144 cubic inches) or the equivalent.
Board feet is calculated by multiplying the surface measure by the standard thickness, except that standard thicknesses less than 1" are measured as 1". Here is the formula for calculating a board foot: length (in feet) x width (in inches) divided by 12 x thickness (in inches). In surfaced lumber, board footage is measured before surfacing (learn more about surface smoothness here).
Board foot calculator
Here is Forest 2 Home's board foot calculation guide for when you're calculating price per board foot or tallying board foot needed for your next woodworking project.
You’ll want to save this handy board foot calculator (screenshot to save in your photos or notes section of your phone) for when you’re figuring out how to get the most bang for your buck at the lumber store. Hint: F2H thickness is actually 15/16” and our widths and lengths are FULL inches. This is not common practice at big box stores where you will see 6” wide boards actually measure up to be 5.5”.