IPv4 Subnet Calculator

Calculate IPv4 network address, subnet mask, wildcard mask, broadcast, usable host range and host count from CIDR notation or an address plus netmask. Free, runs in your browser.



How to use it
  1. Enter an address with a prefix length (e.g. 10.0.0.5/23) or an address plus a dotted netmask.
  2. Read the network, broadcast, usable host range, wildcard mask (useful for Cisco ACLs) and total / usable host counts.
  3. /31 is a point-to-point link (RFC 3021) with 2 usable addresses and no broadcast; /32 is a single host.
  4. Need IPv6? Use the IPv6 Subnet Calculator.


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