LanCalculator is capable of calculating subnet addresses and masks.
LanCalculator makes it possible to calculate the subnet addresses range and subnet masks quickly and broadcast address, net address, net prefix, and netmask inversion, which is used in the access control lists (ACL) of Cisco network equipment. One keypress is enough to calculate all parameters after entering a net address and mask.
LanCalculator provides you with full details on network configuration and calculates subnet parameters quickly. Once you enter the IP address and select one of the additional criteria (subnet prefix, number of subnet bits, the maximum number of subnets, or maximum number of hosts per subnet), LanCalculator will generate a list of all subnets with their parameters.
All the data provided by LanCalculator (including IP addresses, networks, subnets, and their IP addresses) can be easily copied to Clipboard or saved to a file.
Support for all IPv4 and IPv6 address formats
Support for both subnet masks and prefixes
Automatic detection of local IP addresses based on network adapters
Calculation of parameters for both IPv4 and IPv6 networks
IP addresses in binary, octal, decimal or hexadecimal
Support for expanded and compressed IPv6 addresses
Network type detection
Detection of the address range actually used
Creation and export of a list of IP addresses in each subnet
It is free, however, you will need to fill out an online registration form to receive the activation code if not you are given a 30-day trial. There is also a business license available for $49.95 allowing commercial use.