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IPv4 subnet calculator

Compute network/broadcast addresses, netmask, and host range from an IPv4 address and CIDR prefix.

Enter IPv4 address and CIDR prefix length to calculate Network address, Broadcast address, Netmask, First host, Last host, Total addresses, and Usable hosts. Results update instantly as you type. Try an example preset to sanity-check the tool.

Inputs

Dotted-quad IPv4 address (0–255 in each octet).
Examples: /24, /16, /30, /32.
Examples
About this tool
  • Inputs: IPv4 address, CIDR prefix length
  • Outputs: Network address, Broadcast address, Netmask, First host, Last host, Total addresses, Usable hosts
References
  • RFC 4632 (Classless Inter-domain Routing (CIDR))
  • RFC 3021 (/31 for point-to-point links)
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