Processed in your browser. The input is not sent to our server.
How to use this tool
- Enter an IPv4 or IPv6 address followed by /prefix. IPv4 prefixes run from 0 to 32; IPv6 prefixes run from 0 to 128.
- For example, 192.168.10.25/24 yields the network 192.168.10.0/24 and the inclusive range 192.168.10.0 to 192.168.10.255.
How to read the result
Network is the aligned CIDR block. First and last are the inclusive numerical boundaries; count is the total number of addresses in the block. IPv6 counts are exact integer strings. The count is not a count of usable hosts, active devices or assigned VPN peers.
What this tool can establish
Use the result to inspect intended ranges for routes and AllowedIPs. The calculator cannot see existing routes, subnet conflicts, address assignments or firewall permissions on your device.
Privacy and data handling
The calculation runs locally in your browser and does not transmit the address or prefix. It uses integer arithmetic for both address families.