Networking - Reference - Hex / Decimal / Binary Conversion Chart
For anyone who has ever had to sit down and figure conversions without access to the internet or a fancy calculator, you may find this conversion chart somewhat handy. It is something that if you memorize the patterns, you can reproduce on-the-fly. If you are figuring out subnets, just remember that the left-hand side represents the left four binary digits of an octet, while the right-hand side represents the right four binary digits of an octet.
I've attached a zip file which contains the chart in .XLS format.
Enjoy!