Here is a bare-bones board foot calculator for tallying up lumber requirements. Just enter your desired thickness, width, length, and quantity and it will compute board feet and total board feet. Nice and simple. If you want something a little more elaborate that can also produce a materials list, check out the Tabulator.
1. Hardwood lumber is typically sold by the board foot, a unit of volume equivalent to a board that is one inch thick, one foot wide and one foot long, or 144 cubic inches. Lumber thickness is expressed in quarters of an inch, beginning with 1 inch, so that 1 inch lumber is designated as 4/4, 1-1/2 inch lumber is 6/4, 2 inch lumber is 8/4, and so on. These units refer to nominal or roughsawn dimensions, not surfaced dimensions.
2. This program rounds lumber thickness up to the next 1/4″ and lumber less than 4/4 is rounded up to 4/4. Thus, a specified thickness of 3/4″ will be treated as 4/4″ material.
3. You can enter fractional wood dimensions as decimals (12.75), or as conventional fractions (12 3/4). If you use fractions, just make sure you leave a space between any leading whole number and the fraction.