3.14x radius squared will give you the area of the end of the log. You can measure two ways across it and take an average. Usually to get scale you measure from the small end. If you measure in inches you will get sq inches. divide that by 144 to get sq ft, and divide that by 12to get bd ft, and multiply lengh of log for total bd ft. Or pick up a scalebook and it will do the figuring for you.