18.80.0.0/12
PublicClass A — /12 prefix — 1,048,574 usable hosts
Network address — the base address of the block (18.80.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 18.95.255.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 1,048,574 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.240.0.0 is the dotted-decimal equivalent of /12. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 18.80.0.0/12 |
| Network Address | 18.80.0.0 |
| Broadcast Address | 18.95.255.255 |
| Subnet Mask | 255.240.0.0 |
| Wildcard Mask | 0.15.255.255 |
| Prefix Length | /12 |
| IP Address Class | Class A |
| Total IP Addresses | 1,048,576 |
| Usable Host Addresses | 1,048,574 |
| First Usable IP | 18.80.0.1 |
| Last Usable IP | 18.95.255.254 |
| Network (Hex) | 0x12500000 |
| Broadcast (Hex) | 0x125FFFFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 12 bits (1s in the mask) identify the network. The remaining 20 bits identify hosts within the network.
Subnet Breakdown — splitting into /13
This /12 block can be divided into 2 /13 subnets.
| CIDR | Network | Broadcast | First Usable | Last Usable | Hosts |
|---|---|---|---|---|---|
| 18.80.0.0/13 | 18.80.0.0 | 18.87.255.255 | 18.80.0.1 | 18.87.255.254 | 524,286 |
| 18.88.0.0/13 | 18.88.0.0 | 18.95.255.255 | 18.88.0.1 | 18.95.255.254 | 524,286 |