Hello, Beautiful Poison. It's nice to meet you.<br/><br/>There is no real breakdown on the power scale. Just be very careful about throwing in an S rank as that basically means your character is one of the best of the best in  that attribute in that rank.<br/><br/>The way I think about it is that an S rank average will put you on par with Mirajane, Laxus, or Erza.<br/><br/>A to A+ average puts you at about the same level as Gray, Natsu, Elfmann, Levy and the other  S-class trial candidates.<br/><br/>An average of B+ to A- would put you at the level of Lucy, while an average of B- to B would put you on the same level as the other named but not so prominent mages in Fairy Tail such as Jet and Droy.<br/><br/>A C rank would be average and D below average.<br/><br/>This is not the formal rating as we don't have one but I think it works as a good rough estimate. I'm sure Toughie will correct me if I'm wrong or has a better way to look at things.