166.64.224.0/21
PublicClass B — /21 prefix — 2,046 usable hosts
Network address — the base address of the block (166.64.224.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 166.64.231.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 2,046 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.248.0 is the dotted-decimal equivalent of /21. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 166.64.224.0/21 |
| Network Address | 166.64.224.0 |
| Broadcast Address | 166.64.231.255 |
| Subnet Mask | 255.255.248.0 |
| Wildcard Mask | 0.0.7.255 |
| Prefix Length | /21 |
| IP Address Class | Class B |
| Total IP Addresses | 2,048 |
| Usable Host Addresses | 2,046 |
| First Usable IP | 166.64.224.1 |
| Last Usable IP | 166.64.231.254 |
| Network (Hex) | 0xA640E000 |
| Broadcast (Hex) | 0xA640E7FF |
| Address Type | Public / Globally Routable |
Binary Representation
The first 21 bits (1s in the mask) identify the network. The remaining 11 bits identify hosts within the network.
Split into Equal Subnets
Split 166.64.224.0/21 into 2 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 166.64.224.0/22 | 166.64.224.0 | 166.64.224.1 | 166.64.227.254 | 166.64.227.255 | 1,022 |
| 2 | 166.64.228.0/22 | 166.64.228.0 | 166.64.228.1 | 166.64.231.254 | 166.64.231.255 | 1,022 |
Split 166.64.224.0/21 into 4 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 166.64.224.0/23 | 166.64.224.0 | 166.64.224.1 | 166.64.225.254 | 166.64.225.255 | 510 |
| 2 | 166.64.226.0/23 | 166.64.226.0 | 166.64.226.1 | 166.64.227.254 | 166.64.227.255 | 510 |
| 3 | 166.64.228.0/23 | 166.64.228.0 | 166.64.228.1 | 166.64.229.254 | 166.64.229.255 | 510 |
| 4 | 166.64.230.0/23 | 166.64.230.0 | 166.64.230.1 | 166.64.231.254 | 166.64.231.255 | 510 |
Split 166.64.224.0/21 into 8 equal /24 subnets (254 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 166.64.224.0/24 | 166.64.224.0 | 166.64.224.1 | 166.64.224.254 | 166.64.224.255 | 254 |
| 2 | 166.64.225.0/24 | 166.64.225.0 | 166.64.225.1 | 166.64.225.254 | 166.64.225.255 | 254 |
| 3 | 166.64.226.0/24 | 166.64.226.0 | 166.64.226.1 | 166.64.226.254 | 166.64.226.255 | 254 |
| 4 | 166.64.227.0/24 | 166.64.227.0 | 166.64.227.1 | 166.64.227.254 | 166.64.227.255 | 254 |
| 5 | 166.64.228.0/24 | 166.64.228.0 | 166.64.228.1 | 166.64.228.254 | 166.64.228.255 | 254 |
| 6 | 166.64.229.0/24 | 166.64.229.0 | 166.64.229.1 | 166.64.229.254 | 166.64.229.255 | 254 |
| 7 | 166.64.230.0/24 | 166.64.230.0 | 166.64.230.1 | 166.64.230.254 | 166.64.230.255 | 254 |
| 8 | 166.64.231.0/24 | 166.64.231.0 | 166.64.231.1 | 166.64.231.254 | 166.64.231.255 | 254 |
Split 166.64.224.0/21 into 16 equal /25 subnets (126 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 166.64.224.0/25 | 166.64.224.0 | 166.64.224.1 | 166.64.224.126 | 166.64.224.127 | 126 |
| 2 | 166.64.224.128/25 | 166.64.224.128 | 166.64.224.129 | 166.64.224.254 | 166.64.224.255 | 126 |
| 3 | 166.64.225.0/25 | 166.64.225.0 | 166.64.225.1 | 166.64.225.126 | 166.64.225.127 | 126 |
| 4 | 166.64.225.128/25 | 166.64.225.128 | 166.64.225.129 | 166.64.225.254 | 166.64.225.255 | 126 |
| 5 | 166.64.226.0/25 | 166.64.226.0 | 166.64.226.1 | 166.64.226.126 | 166.64.226.127 | 126 |
| 6 | 166.64.226.128/25 | 166.64.226.128 | 166.64.226.129 | 166.64.226.254 | 166.64.226.255 | 126 |
| 7 | 166.64.227.0/25 | 166.64.227.0 | 166.64.227.1 | 166.64.227.126 | 166.64.227.127 | 126 |
| 8 | 166.64.227.128/25 | 166.64.227.128 | 166.64.227.129 | 166.64.227.254 | 166.64.227.255 | 126 |
| 9 | 166.64.228.0/25 | 166.64.228.0 | 166.64.228.1 | 166.64.228.126 | 166.64.228.127 | 126 |
| 10 | 166.64.228.128/25 | 166.64.228.128 | 166.64.228.129 | 166.64.228.254 | 166.64.228.255 | 126 |
| 11 | 166.64.229.0/25 | 166.64.229.0 | 166.64.229.1 | 166.64.229.126 | 166.64.229.127 | 126 |
| 12 | 166.64.229.128/25 | 166.64.229.128 | 166.64.229.129 | 166.64.229.254 | 166.64.229.255 | 126 |
| 13 | 166.64.230.0/25 | 166.64.230.0 | 166.64.230.1 | 166.64.230.126 | 166.64.230.127 | 126 |
| 14 | 166.64.230.128/25 | 166.64.230.128 | 166.64.230.129 | 166.64.230.254 | 166.64.230.255 | 126 |
| 15 | 166.64.231.0/25 | 166.64.231.0 | 166.64.231.1 | 166.64.231.126 | 166.64.231.127 | 126 |
| 16 | 166.64.231.128/25 | 166.64.231.128 | 166.64.231.129 | 166.64.231.254 | 166.64.231.255 | 126 |