Swing-weight is essentially the effort required by the hitter to move the bat through a full swing.  The
swing-weight of a bat depends on the length, shape, and weight.  This scale is meant to be a tool for comparing the swing-weight of any baseball or softball bat.  It is based on the industry standard method (ASTM F2398) for measuring the MOI (moment of inertia) of a bat.  This scale does not just compare the MOI , but instead translates that MOI onto a scale with a simple number rating (SW#) for each bat. Bats with a lower number will be easier to get through the zone, while those with a higher number will be more difficult.  A change of 1 on the scale represents the smallest change in swing weight that a high level baller player could feel and is quite small.  Most players would not be able to tell a difference until a change of 2 or 3. Adding a cup to the end of a wood bat will lower the SW# by 1-2.  Choosing a bell or puck knob instead of our flared, tapered, comfort, or no knob will also lower the SW# by 1-2.  Going up 1oz in weight (ie 33in 31oz) will add 3 to the SW#.