/32 Subnet: Mask 255.255.255.255
A /32 subnet has a subnet mask of 255.255.255.255 and represents a single IP address (1 host). 256 /32 networks fit inside a single /24.
| CIDR notation | /32 |
|---|---|
| Subnet mask | 255.255.255.255 |
| Wildcard mask | 0.0.0.0 |
| Mask in binary | 11111111.11111111.11111111.11111111 |
| Total addresses | 1 (2^0) |
| Usable hosts | 1 |
| Host bits | 0 |
Usable hosts in a /32 by platform
Cloud providers reserve more than the usual two addresses per subnet, so the same /32 gives you fewer usable IPs in the cloud than on a standard LAN.
| Platform | Reserved IPs | Usable hosts |
|---|---|---|
| Standard (network + broadcast) | 0 | 1 |
| AWS VPC | 0 | 1 |
| Microsoft Azure VNet | 0 | 1 |
| Google Cloud VPC | 0 | 1 |
| Oracle Cloud VCN | 0 | 1 |
Good to know
A /32 is a single host, one exact IP address. It is used for host routes, loopback interfaces, and firewall or ACL rules that target one machine.
How a /32 is calculated
- The /32 means the first 32 bits are the network portion, leaving 0 host bits.
- Total addresses = 2^(32 - 32) = 2^0 = 1.
- Usable hosts (standard) = 1 = 1.
- Subnet mask = 255.255.255.255; wildcard mask = 0.0.0.0.
Want to split a /32 into smaller subnets, see every address range, or plan a VLSM layout? Open the free subnet calculator →