Whatmask - IPv4 address/mask calculator

Whatmask can be used two ways:
                                                                   Example of query:
Given a mask enter:    CIDR bits                                   20
               - or -  subnet mask                       
               - or -  hex subnet mask                             0xfffff000
               - or -  wildcard bit mask                 
NOTE: whatmask will autodetect the input and show you all four.

Given an ip/mask enter: IP address/netmask                        Example of query:
    where netmask may be one of the following:
                       CIDR notation (e.g. "27")         
                       Netmask notation (e.g. "")
                       Hex Netmask notation (e.g. "0xffffff00")
                       Wildcard bits notation (e.g. "")
NOTE: whatmask will autodetect the netmask format.