28.0.0.0/7
PublicClass A — /7 prefix — 33,554,430 usable hosts
Network address — the base address of the block (28.0.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 29.255.255.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 33,554,430 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 254.0.0.0 is the dotted-decimal equivalent of /7. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 28.0.0.0/7 |
| Network Address | 28.0.0.0 |
| Broadcast Address | 29.255.255.255 |
| Subnet Mask | 254.0.0.0 |
| Wildcard Mask | 1.255.255.255 |
| Prefix Length | /7 |
| IP Address Class | Class A |
| Total IP Addresses | 33,554,432 |
| Usable Host Addresses | 33,554,430 |
| First Usable IP | 28.0.0.1 |
| Last Usable IP | 29.255.255.254 |
| Network (Hex) | 0x1C000000 |
| Broadcast (Hex) | 0x1DFFFFFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 7 bits (1s in the mask) identify the network. The remaining 25 bits identify hosts within the network.
Split into Equal Subnets
Split 28.0.0.0/7 into 2 equal /8 subnets (16,777,214 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.0.0.0/8 | 28.0.0.0 | 28.0.0.1 | 28.255.255.254 | 28.255.255.255 | 16,777,214 |
| 2 | 29.0.0.0/8 | 29.0.0.0 | 29.0.0.1 | 29.255.255.254 | 29.255.255.255 | 16,777,214 |
Split 28.0.0.0/7 into 4 equal /9 subnets (8,388,606 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.0.0.0/9 | 28.0.0.0 | 28.0.0.1 | 28.127.255.254 | 28.127.255.255 | 8,388,606 |
| 2 | 28.128.0.0/9 | 28.128.0.0 | 28.128.0.1 | 28.255.255.254 | 28.255.255.255 | 8,388,606 |
| 3 | 29.0.0.0/9 | 29.0.0.0 | 29.0.0.1 | 29.127.255.254 | 29.127.255.255 | 8,388,606 |
| 4 | 29.128.0.0/9 | 29.128.0.0 | 29.128.0.1 | 29.255.255.254 | 29.255.255.255 | 8,388,606 |
Split 28.0.0.0/7 into 8 equal /10 subnets (4,194,302 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.0.0.0/10 | 28.0.0.0 | 28.0.0.1 | 28.63.255.254 | 28.63.255.255 | 4,194,302 |
| 2 | 28.64.0.0/10 | 28.64.0.0 | 28.64.0.1 | 28.127.255.254 | 28.127.255.255 | 4,194,302 |
| 3 | 28.128.0.0/10 | 28.128.0.0 | 28.128.0.1 | 28.191.255.254 | 28.191.255.255 | 4,194,302 |
| 4 | 28.192.0.0/10 | 28.192.0.0 | 28.192.0.1 | 28.255.255.254 | 28.255.255.255 | 4,194,302 |
| 5 | 29.0.0.0/10 | 29.0.0.0 | 29.0.0.1 | 29.63.255.254 | 29.63.255.255 | 4,194,302 |
| 6 | 29.64.0.0/10 | 29.64.0.0 | 29.64.0.1 | 29.127.255.254 | 29.127.255.255 | 4,194,302 |
| 7 | 29.128.0.0/10 | 29.128.0.0 | 29.128.0.1 | 29.191.255.254 | 29.191.255.255 | 4,194,302 |
| 8 | 29.192.0.0/10 | 29.192.0.0 | 29.192.0.1 | 29.255.255.254 | 29.255.255.255 | 4,194,302 |
Split 28.0.0.0/7 into 16 equal /11 subnets (2,097,150 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 28.0.0.0/11 | 28.0.0.0 | 28.0.0.1 | 28.31.255.254 | 28.31.255.255 | 2,097,150 |
| 2 | 28.32.0.0/11 | 28.32.0.0 | 28.32.0.1 | 28.63.255.254 | 28.63.255.255 | 2,097,150 |
| 3 | 28.64.0.0/11 | 28.64.0.0 | 28.64.0.1 | 28.95.255.254 | 28.95.255.255 | 2,097,150 |
| 4 | 28.96.0.0/11 | 28.96.0.0 | 28.96.0.1 | 28.127.255.254 | 28.127.255.255 | 2,097,150 |
| 5 | 28.128.0.0/11 | 28.128.0.0 | 28.128.0.1 | 28.159.255.254 | 28.159.255.255 | 2,097,150 |
| 6 | 28.160.0.0/11 | 28.160.0.0 | 28.160.0.1 | 28.191.255.254 | 28.191.255.255 | 2,097,150 |
| 7 | 28.192.0.0/11 | 28.192.0.0 | 28.192.0.1 | 28.223.255.254 | 28.223.255.255 | 2,097,150 |
| 8 | 28.224.0.0/11 | 28.224.0.0 | 28.224.0.1 | 28.255.255.254 | 28.255.255.255 | 2,097,150 |
| 9 | 29.0.0.0/11 | 29.0.0.0 | 29.0.0.1 | 29.31.255.254 | 29.31.255.255 | 2,097,150 |
| 10 | 29.32.0.0/11 | 29.32.0.0 | 29.32.0.1 | 29.63.255.254 | 29.63.255.255 | 2,097,150 |
| 11 | 29.64.0.0/11 | 29.64.0.0 | 29.64.0.1 | 29.95.255.254 | 29.95.255.255 | 2,097,150 |
| 12 | 29.96.0.0/11 | 29.96.0.0 | 29.96.0.1 | 29.127.255.254 | 29.127.255.255 | 2,097,150 |
| 13 | 29.128.0.0/11 | 29.128.0.0 | 29.128.0.1 | 29.159.255.254 | 29.159.255.255 | 2,097,150 |
| 14 | 29.160.0.0/11 | 29.160.0.0 | 29.160.0.1 | 29.191.255.254 | 29.191.255.255 | 2,097,150 |
| 15 | 29.192.0.0/11 | 29.192.0.0 | 29.192.0.1 | 29.223.255.254 | 29.223.255.255 | 2,097,150 |
| 16 | 29.224.0.0/11 | 29.224.0.0 | 29.224.0.1 | 29.255.255.254 | 29.255.255.255 | 2,097,150 |