VERY illustrative...from the NY Times.
Real Clear Politics has this to say about the calculator:
Determining the degree to which Clinton can close the pledged delegate gap in the remaining primaries might lead the average Clinton supporter to be fairly skeptical of her chances at the nomination. The new New York Times Delegate Calculator (rereleased Monday) puts this in even greater perspective. It factors in the percentage of remaining super delegates Clinton would need to win assuming she receives a certain percentage of the remaining pledged delegates.
What does it reveal?
If Clinton were to win a generous 57 percent of the pledged delegates in the remaining states, she would still need 63 percent of the undecided super delegates remaining to win the nomination. Clinton won 53.7% of the pledged delegates from her Pennsylvania victory and 52.4% of the pledged delegates from her Ohio victory.
A more revealing way to put it would be that Obama could manage only 43% of the pledged delegates in the remaining primaries and still need only 38% of the undecided super delegates to back him.
Based on recent super delegate trends even after Obamaâ€™s most recent struggles, such a wave of Clinton support among super delegates appears to be quite a daunting task.