Subnet Calculator

Subnet Calculator puts essential subnet math in your pocket. Enter any IP and CIDR, and instantly see network address, broadcast, usable range, and more—ideal for admins, developers, and anyone planning or troubleshooting networks.

► Subnet Calculator
• Support for IPv4 and IPv6; switch between them with a single tap.
• Enter any IP address and adjust CIDR prefix length with a slider (/0 to /32 for IPv4, /0 to /128 for IPv6).
• Instant results: network address, subnet mask, broadcast, first and last usable IP, host range, and total addresses.
• IPv4: see address class (A/B/C/D/E), wildcard mask, and usable host count.
• IPv6: see prefix length and total addresses in compact form (K, M, B).
• Long-press any result to copy it to the clipboard.

► General
• Dark and light theme.
• Portrait-oriented layout for one-handed use.
• No account required. Free to use, with ads to support development.

Built for quick subnet planning, subnetting practice, and network design—handy for home labs, offices, and developers.