LanCalculator - IP Subnet Calculator for IPv4/IPv6 Networks - LizardSystems
RackNerd - IPv4 Calculator and IPv6 Calculator — RackNerd
IP Subnet Calculator | IPTP Networks
GitHub - ygvn/IPv6-Subnet-Calculator-Tool-JavaFX: IPv6 Subnet Calculator / Tool application lets you plan/subnet your assigned IPv6 address for all 128 bits.
Site24x7 Subnet Calculator for IPv4 and IPv6: Network IP Calculations Made Simple - Site24x7 Blog