IP / CIDR Calculator
Calculate network address, broadcast, usable hosts, subnet mask, and binary representation for IPv4 and IPv6 CIDR blocks.
Split a network into smaller subnets by specifying the new prefix length.
| # | Network | First host | Last host | Broadcast | Hosts |
|---|
How it works
CIDR (Classless Inter-Domain Routing) - The prefix length (e.g. /24) specifies how many bits are the network portion. The remaining bits identify hosts within the network.
Network address - IP ANDed with subnet mask. First address of the subnet. Not assignable to hosts.
Broadcast address - IP ORed with inverted mask. Last address. Not assignable to hosts. Packets sent here reach all hosts in the subnet.
Usable hosts - 2^(32−prefix) − 2 (subtract network and broadcast). /30 gives 2 usable hosts; /31 gives 0 (used for point-to-point links with no broadcast).