IPv4 addresses and usable hosts from a prefix length.
| Addresses | – |
| Hosts | – |
Use this calculator when a network is written as /24 and you need the size of the block.
Addresses = 2^(32 − prefix). Usable hosts are usually addresses minus network and broadcast, so a /24 has 256 addresses and 254 hosts. /31 is two addresses for a point-to-point link (RFC 3021). /32 is a single host. /0 is the whole IPv4 space. IPv6 is not this tool.
Prefix: Bits in the network mask, 0 to 32.
Addresses: Size of the block.
Hosts: Usable host count with the /31 and /32 exceptions.
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