IT Consulting
Illustration of a CIDR block 192.168.1.0/24 splitting into network address, broadcast address, and usable host range chips

IP/Subnet Calculator

Enter an IPv4 address with a CIDR prefix (e.g. 192.168.1.10/24). Runs entirely in your browser.

ℹ️ How this works
  • The prefix (e.g. /24) determines the netmask; the network address is your IP with all host bits zeroed, and the broadcast address is the network address with all host bits set to 1.
  • Usable hosts excludes the network and broadcast addresses — except /31 (both addresses usable, RFC 3021, common on point-to-point links) and /32 (a single host, no broadcast concept).
  • IPv4 only on this page — broadcast addresses don't exist in IPv6. The JSON API below also accepts IPv6 CIDR input.
  • Runs entirely client-side — nothing you enter here is ever sent anywhere.
💻 Show API usage example (cURL) 
curl -sS "https://devops.majbase.com/subnet-calculator/api?cidr=192.168.1.10/24"

Returns JSON: {"network_address", "broadcast_address", "netmask", "wildcard_mask", "total_addresses", "usable_hosts_count", "first_usable", "last_usable", "is_private", ...}. Also accepts IPv6 input (e.g. 2001:db8::1/64) — broadcast_address is simply omitted there, since IPv6 has no broadcast concept.