Most sawmills sell lumber based on a unit of measurement called a board foot. A board foot is the volume of wood equal to a piece I inch thick by 12 inches wide by 1 foot long. The following formula is used to calculate the board foot volume in a board:   

All dimensions are based on the rough sawn size of the board, even if the lumber is being sold as planed or surfaced. Pricing is generally quoted per thousand board feet (MBF).   

Most hardwood lumber is produced and sold in random widths and mixed lengths. In most cases, it is not possible to purchase hardwoods in fixed widths and lengths from a sawmill.   

Softwood lumber for construction is commonly manufactured by specific dimensions. For instance, you can buy any number of boards 1 inch thick by 4 inches wide by 8 feet long (1x4x8's). This material is sold by the piece, by the linear foot or by the board foot. The following chart can be used as a reference to calculate board footage of softwood lumber.