Damage Calc.
I've looked around and I've found a few, but most of them are cumbersome to use and require some sort of external resource for finding stats at L100. Right now I mostly use the Libelldra calculator, and every time I want to do something I have to open Shoddy, make a new team, put in different EVs, and figure out what stats to input from there. It's really time-consuming and gets annoying quickly.
Is there a calculator that you can use just by choosing the attacking and defending Pokemon, natures, and EVs?
This question came mostly from reading around and seeing posts like
http://www.smogon.com/forums/showpost.php?p=1757974&postcount=1301 and
http://www.smogon.com/forums/showpost.php?p=1760368&postcount=3. It seems like it would take an insanely long time to do those calcs if one had to figure out what EVs yielded what stats manually.