Does its job
Does what I need it to do for the most part. Something seems weird with the supernetting section under the CIDR tab. When you change mask bits it doesn't change the mask.
Missing IP addresses and subnets.
Missing subnet calculation for IPv6
Four tabs--four tasks. This calculator is great for doing the task at hand, and presents the information clearly. However, I think there is a little too much whitespace, especially in the CIDR tab. As a CCNA student, it's a great tool while I try to wrap my head around subnetting, while not getting left behind during lectures.