/2 Subnet: Mask 192.0.0.0, 1,073,741,822 Usable Hosts
A /2 subnet has a subnet mask of 192.0.0.0 and contains 1,073,741,824 total IP addresses, of which 1,073,741,822 are usable host addresses (the network and broadcast addresses are reserved). A /2 contains 4,194,304 /24 networks.
| CIDR notation | /2 |
|---|---|
| Subnet mask | 192.0.0.0 |
| Wildcard mask | 63.255.255.255 |
| Mask in binary | 11000000.00000000.00000000.00000000 |
| Total addresses | 1,073,741,824 (2^30) |
| Usable hosts | 1,073,741,822 |
| Host bits | 30 |
Usable hosts in a /2 by platform
Cloud providers reserve more than the usual two addresses per subnet, so the same /2 gives you fewer usable IPs in the cloud than on a standard LAN.
| Platform | Reserved IPs | Usable hosts |
|---|---|---|
| Standard (network + broadcast) | 2 | 1,073,741,822 |
| AWS VPC | 5 | 1,073,741,819 |
| Microsoft Azure VNet | 5 | 1,073,741,819 |
| Google Cloud VPC | 4 | 1,073,741,820 |
| Oracle Cloud VCN | 3 | 1,073,741,821 |
Good to know
A /2 subnet has a 192.0.0.0 mask and 1,073,741,824 total addresses (1,073,741,822 usable). Each step from /2 to /3 halves the block; each step back to /1 doubles it.
How a /2 is calculated
- The /2 means the first 2 bits are the network portion, leaving 30 host bits.
- Total addresses = 2^(32 - 2) = 2^30 = 1,073,741,824.
- Usable hosts (standard) = 1,073,741,824 - 2 (network + broadcast) = 1,073,741,822.
- Subnet mask = 192.0.0.0; wildcard mask = 63.255.255.255.
Want to split a /2 into smaller subnets, see every address range, or plan a VLSM layout? Open the free subnet calculator →