Calculating Board Feet

Once you have selected boards of a certain species, cut, width, thickness and grade, it will have to be measured for sale. Lumber is generally sold by the board foot, abbreviated as BD FT. Recently I bought some top grade Honduras mahogany for carving signs. I paid $5.95 per board foot for 8/4 stock. The price will vary depending upon the thickness, which was actual as it was not surfaced. To calculate the cost of the lumber we had to measure it to find out how many board feet of mahogany were there. To do that you need to know exactly what a board foot is.

One board foot of lumber is one foot long by one foot wide by one inch thick. Or it can be two feet long by 6 inches wide by one inch thick. Basically, no matter how you look at it, it is 144 cubic inches of wood. I prefer to calculate it by simplifying things and converting all my units to inches. My mahogany was just a hair over fourteen feet long which is 168 inches. It was 7 inches wide and 2 inches thick, as it was 8/4 stock. Finding the volume of a rectangular prism, or length x width x thickness, we have 168 x 7 x 2 or 2352 cubic inches. Divide that by 144, or the number of cubic inches in one BD FT, and we get 16.33 BD FT. At $5.95 per BD FT, that piece of wood cost me $97.16 to buy. It’s simple. Just find the volume of the board in inches, and divide by 144. The only thing to remember is to verify with the proprietor how he measures before buying, especially if the board has an irregular shape such as a waney edge.