I didn't make this calculator I only found it. I assume its made by kunzite because it was one his website. The calculator is great because it lets you input your own server prices and see what craftable item is most profitable to disenchant.
http://www.mmorpgs.com/Kunzite/guide/disenchant.php
No I don't want rep for this because I didn't create the calculator but if you want feel free I need 2 more to enter trade forums which I need to use