Because girth isn't consistent along the shaft, this measurement is completely inaccurate. The only conclusive measurement of size is volume. This would be given in milliliters. the test for this is done as follows. Fill a large beaker to a known volume to the top. Insert fully erect cock downward into water. The amount of displaced water represents the volume of the inserted penis. Giving numbers of length and girth are completely inaccurate and only serve to give a general idea of size.