Host route. Single host address. Used for loopback interfaces and specific route advertisements.
Single host address. Used for loopback interfaces and specific route advertisements.
The /32 subnet uses 255.255.255.255 as its subnet mask — meaning the first 32 bits of every address identify the network, and the remaining 0 bits identify the host within that network. That gives you 1 total addresses (1 usable on standard RFC math, after subtracting the network and broadcast addresses).
The wildcard mask — the bitwise inverse of the subnet mask — is 0.0.0.0. Wildcards are what Cisco access-control lists and OSPF area definitions use instead of subnet masks; the "1" bits mark "don't care" positions. For a /32, that leaves 0 don't-care host bits.
To find the network address for any IP in a /32 block, perform a bitwise AND between the IP and the subnet mask. To find the broadcast, OR the network address with the wildcard. Modern tools — like our subnet calculator — do this in microseconds, but the underlying mechanics are straightforward binary arithmetic.
A /32 is a host route. One single IP. Used for routing decisions, load-balancer VIPs, BGP loopback interfaces, and DNS A-record targets. Not a subnet you assign hosts to — it identifies a single endpoint.
Cloud-provider quirks matter at every prefix size: AWS and Azure reserve 5 IPs per subnet, GCP reserves 4, and OCI reserves 3. So a /32 on standard RFC math gives you 1 usable hosts, but on AWS or Azure that drops to 0. The capacity-planning gap bites hardest at small prefixes (a /28 has 14 usable on paper, only 11 on AWS) but exists at every size. Our cloud-aware calculator applies the right math automatically.
A /32 subnet has 1 usable hosts on standard RFC math. On AWS or Azure (which reserve 5 IPs per subnet), you get 0 usable. On GCP (4 reserved), 0. On OCI (3 reserved), 0.
The /32 prefix corresponds to subnet mask 255.255.255.255. The matching wildcard mask (used in Cisco ACLs) is 0.0.0.0.
Apply a bitwise AND between the IP and the subnet mask to get the network address. OR the network address with the wildcard mask to get the broadcast. For example, 192.168.1.0/32 has 1 total addresses, with the first being the network address and the last being the broadcast.
A /32 identifies a single host or routing target. Common uses include loopback addresses on routers, BGP peer endpoints, load-balancer VIPs, and explicit host routes injected into a routing table. A /32 is not a subnet you assign hosts to — it represents exactly one IP.