How do I calculate board feet to square feet?

Square feet is length times width. For example if you have an 8 foot 1x12, it would be 7.7 square feet. The reason being is that 1 x 12's are actually 3/4" x 11.5" boards. Your equation would look like this:

8 x 11.5/12 =
8 x 0.96 = 7.7 square feet. Always keep in mind that all units that you are multiplying by have to be the same. That is the reason I divided the 11.5 inches by 12 to convert it to feet.

Board foot is calculated as 1 foot x 1 foot x 1 inch thickness. So an 8 foot board that is 12" wide and 1" thick would be 8 board feet. Think you are calculating volume. The formula for calculating a board's volume is, length/12 times width times height or thickness. Using the 8 foot 1 x 12 in our first example, the board food would be 5.75 board feet.

You equation would look like this:

8/12 (which is the lenght) x 0.75 (which is the thickness) x 11.5 (which is the width = 5.75 board feet.