/5 Subnet: Mask 248.0.0.0, 134,217,726 Usable Hosts
A /5 subnet has a subnet mask of 248.0.0.0 and contains 134,217,728 total IP addresses, of which 134,217,726 are usable host addresses (the network and broadcast addresses are reserved). A /5 contains 524,288 /24 networks.
| CIDR notation | /5 |
|---|---|
| Subnet mask | 248.0.0.0 |
| Wildcard mask | 7.255.255.255 |
| Mask in binary | 11111000.00000000.00000000.00000000 |
| Total addresses | 134,217,728 (2^27) |
| Usable hosts | 134,217,726 |
| Host bits | 27 |
Usable hosts in a /5 by platform
Cloud providers reserve more than the usual two addresses per subnet, so the same /5 gives you fewer usable IPs in the cloud than on a standard LAN.
| Platform | Reserved IPs | Usable hosts |
|---|---|---|
| Standard (network + broadcast) | 2 | 134,217,726 |
| AWS VPC | 5 | 134,217,723 |
| Microsoft Azure VNet | 5 | 134,217,723 |
| Google Cloud VPC | 4 | 134,217,724 |
| Oracle Cloud VCN | 3 | 134,217,725 |
Good to know
A /5 subnet has a 248.0.0.0 mask and 134,217,728 total addresses (134,217,726 usable). Each step from /5 to /6 halves the block; each step back to /4 doubles it.
How a /5 is calculated
- The /5 means the first 5 bits are the network portion, leaving 27 host bits.
- Total addresses = 2^(32 - 5) = 2^27 = 134,217,728.
- Usable hosts (standard) = 134,217,728 - 2 (network + broadcast) = 134,217,726.
- Subnet mask = 248.0.0.0; wildcard mask = 7.255.255.255.
Want to split a /5 into smaller subnets, see every address range, or plan a VLSM layout? Open the free subnet calculator →