121.2.0.0/16
PublicClass A — /16 prefix — 65,534 usable hosts
Network address — the base address of the block (121.2.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 121.2.255.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 65,534 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.0.0 is the dotted-decimal equivalent of /16. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 121.2.0.0/16 |
| Network Address | 121.2.0.0 |
| Broadcast Address | 121.2.255.255 |
| Subnet Mask | 255.255.0.0 |
| Wildcard Mask | 0.0.255.255 |
| Prefix Length | /16 |
| IP Address Class | Class A |
| Total IP Addresses | 65,536 |
| Usable Host Addresses | 65,534 |
| First Usable IP | 121.2.0.1 |
| Last Usable IP | 121.2.255.254 |
| Network (Hex) | 0x79020000 |
| Broadcast (Hex) | 0x7902FFFF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 16 bits (1s in the mask) identify the network. The remaining 16 bits identify hosts within the network.
Split into Equal Subnets
Split 121.2.0.0/16 into 2 equal /17 subnets (32,766 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 121.2.0.0/17 | 121.2.0.0 | 121.2.0.1 | 121.2.127.254 | 121.2.127.255 | 32,766 |
| 2 | 121.2.128.0/17 | 121.2.128.0 | 121.2.128.1 | 121.2.255.254 | 121.2.255.255 | 32,766 |
Split 121.2.0.0/16 into 4 equal /18 subnets (16,382 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 121.2.0.0/18 | 121.2.0.0 | 121.2.0.1 | 121.2.63.254 | 121.2.63.255 | 16,382 |
| 2 | 121.2.64.0/18 | 121.2.64.0 | 121.2.64.1 | 121.2.127.254 | 121.2.127.255 | 16,382 |
| 3 | 121.2.128.0/18 | 121.2.128.0 | 121.2.128.1 | 121.2.191.254 | 121.2.191.255 | 16,382 |
| 4 | 121.2.192.0/18 | 121.2.192.0 | 121.2.192.1 | 121.2.255.254 | 121.2.255.255 | 16,382 |
Split 121.2.0.0/16 into 8 equal /19 subnets (8,190 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 121.2.0.0/19 | 121.2.0.0 | 121.2.0.1 | 121.2.31.254 | 121.2.31.255 | 8,190 |
| 2 | 121.2.32.0/19 | 121.2.32.0 | 121.2.32.1 | 121.2.63.254 | 121.2.63.255 | 8,190 |
| 3 | 121.2.64.0/19 | 121.2.64.0 | 121.2.64.1 | 121.2.95.254 | 121.2.95.255 | 8,190 |
| 4 | 121.2.96.0/19 | 121.2.96.0 | 121.2.96.1 | 121.2.127.254 | 121.2.127.255 | 8,190 |
| 5 | 121.2.128.0/19 | 121.2.128.0 | 121.2.128.1 | 121.2.159.254 | 121.2.159.255 | 8,190 |
| 6 | 121.2.160.0/19 | 121.2.160.0 | 121.2.160.1 | 121.2.191.254 | 121.2.191.255 | 8,190 |
| 7 | 121.2.192.0/19 | 121.2.192.0 | 121.2.192.1 | 121.2.223.254 | 121.2.223.255 | 8,190 |
| 8 | 121.2.224.0/19 | 121.2.224.0 | 121.2.224.1 | 121.2.255.254 | 121.2.255.255 | 8,190 |
Split 121.2.0.0/16 into 16 equal /20 subnets (4,094 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 121.2.0.0/20 | 121.2.0.0 | 121.2.0.1 | 121.2.15.254 | 121.2.15.255 | 4,094 |
| 2 | 121.2.16.0/20 | 121.2.16.0 | 121.2.16.1 | 121.2.31.254 | 121.2.31.255 | 4,094 |
| 3 | 121.2.32.0/20 | 121.2.32.0 | 121.2.32.1 | 121.2.47.254 | 121.2.47.255 | 4,094 |
| 4 | 121.2.48.0/20 | 121.2.48.0 | 121.2.48.1 | 121.2.63.254 | 121.2.63.255 | 4,094 |
| 5 | 121.2.64.0/20 | 121.2.64.0 | 121.2.64.1 | 121.2.79.254 | 121.2.79.255 | 4,094 |
| 6 | 121.2.80.0/20 | 121.2.80.0 | 121.2.80.1 | 121.2.95.254 | 121.2.95.255 | 4,094 |
| 7 | 121.2.96.0/20 | 121.2.96.0 | 121.2.96.1 | 121.2.111.254 | 121.2.111.255 | 4,094 |
| 8 | 121.2.112.0/20 | 121.2.112.0 | 121.2.112.1 | 121.2.127.254 | 121.2.127.255 | 4,094 |
| 9 | 121.2.128.0/20 | 121.2.128.0 | 121.2.128.1 | 121.2.143.254 | 121.2.143.255 | 4,094 |
| 10 | 121.2.144.0/20 | 121.2.144.0 | 121.2.144.1 | 121.2.159.254 | 121.2.159.255 | 4,094 |
| 11 | 121.2.160.0/20 | 121.2.160.0 | 121.2.160.1 | 121.2.175.254 | 121.2.175.255 | 4,094 |
| 12 | 121.2.176.0/20 | 121.2.176.0 | 121.2.176.1 | 121.2.191.254 | 121.2.191.255 | 4,094 |
| 13 | 121.2.192.0/20 | 121.2.192.0 | 121.2.192.1 | 121.2.207.254 | 121.2.207.255 | 4,094 |
| 14 | 121.2.208.0/20 | 121.2.208.0 | 121.2.208.1 | 121.2.223.254 | 121.2.223.255 | 4,094 |
| 15 | 121.2.224.0/20 | 121.2.224.0 | 121.2.224.1 | 121.2.239.254 | 121.2.239.255 | 4,094 |
| 16 | 121.2.240.0/20 | 121.2.240.0 | 121.2.240.1 | 121.2.255.254 | 121.2.255.255 | 4,094 |