NetCalcTools
The network calculator with many tools for IPv4,IPv6
... - Calculation of subnets for whole network from 1 or multiple input IP addresses.
Other tools:
MAC INFORMATION - Will show information about MAC such as if it's global/local individual/group
IPv6 tools:
SUBNET CALC - Basic calc for IPv6 , Subnet,Host range,Max hosts ...
MULTICAST CALC - Will show information about Multicast IPv6 address for example R,T,P bits .
OPERATIONS - If you need Commpress,expand IPv6