172.31.128.0/19
Private (RFC 1918) RFC 1918Class B — /19 prefix — 8,190 usable hosts
Network address — the base address of the block (172.31.128.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 172.31.159.255 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 8,190 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.224.0 is the dotted-decimal equivalent of /19. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 172.31.128.0/19 |
| Network Address | 172.31.128.0 |
| Broadcast Address | 172.31.159.255 |
| Subnet Mask | 255.255.224.0 |
| Wildcard Mask | 0.0.31.255 |
| Prefix Length | /19 |
| IP Address Class | Class B |
| Total IP Addresses | 8,192 |
| Usable Host Addresses | 8,190 |
| First Usable IP | 172.31.128.1 |
| Last Usable IP | 172.31.159.254 |
| Network (Hex) | 0xAC1F8000 |
| Broadcast (Hex) | 0xAC1F9FFF |
| Governing RFC | RFC 1918 |
| Address Type | Private (RFC 1918) |
Binary Representation
The first 19 bits (1s in the mask) identify the network. The remaining 13 bits identify hosts within the network.
Split into Equal Subnets
Split 172.31.128.0/19 into 2 equal /20 subnets (4,094 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.31.128.0/20 | 172.31.128.0 | 172.31.128.1 | 172.31.143.254 | 172.31.143.255 | 4,094 |
| 2 | 172.31.144.0/20 | 172.31.144.0 | 172.31.144.1 | 172.31.159.254 | 172.31.159.255 | 4,094 |
Split 172.31.128.0/19 into 4 equal /21 subnets (2,046 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.31.128.0/21 | 172.31.128.0 | 172.31.128.1 | 172.31.135.254 | 172.31.135.255 | 2,046 |
| 2 | 172.31.136.0/21 | 172.31.136.0 | 172.31.136.1 | 172.31.143.254 | 172.31.143.255 | 2,046 |
| 3 | 172.31.144.0/21 | 172.31.144.0 | 172.31.144.1 | 172.31.151.254 | 172.31.151.255 | 2,046 |
| 4 | 172.31.152.0/21 | 172.31.152.0 | 172.31.152.1 | 172.31.159.254 | 172.31.159.255 | 2,046 |
Split 172.31.128.0/19 into 8 equal /22 subnets (1,022 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.31.128.0/22 | 172.31.128.0 | 172.31.128.1 | 172.31.131.254 | 172.31.131.255 | 1,022 |
| 2 | 172.31.132.0/22 | 172.31.132.0 | 172.31.132.1 | 172.31.135.254 | 172.31.135.255 | 1,022 |
| 3 | 172.31.136.0/22 | 172.31.136.0 | 172.31.136.1 | 172.31.139.254 | 172.31.139.255 | 1,022 |
| 4 | 172.31.140.0/22 | 172.31.140.0 | 172.31.140.1 | 172.31.143.254 | 172.31.143.255 | 1,022 |
| 5 | 172.31.144.0/22 | 172.31.144.0 | 172.31.144.1 | 172.31.147.254 | 172.31.147.255 | 1,022 |
| 6 | 172.31.148.0/22 | 172.31.148.0 | 172.31.148.1 | 172.31.151.254 | 172.31.151.255 | 1,022 |
| 7 | 172.31.152.0/22 | 172.31.152.0 | 172.31.152.1 | 172.31.155.254 | 172.31.155.255 | 1,022 |
| 8 | 172.31.156.0/22 | 172.31.156.0 | 172.31.156.1 | 172.31.159.254 | 172.31.159.255 | 1,022 |
Split 172.31.128.0/19 into 16 equal /23 subnets (510 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 172.31.128.0/23 | 172.31.128.0 | 172.31.128.1 | 172.31.129.254 | 172.31.129.255 | 510 |
| 2 | 172.31.130.0/23 | 172.31.130.0 | 172.31.130.1 | 172.31.131.254 | 172.31.131.255 | 510 |
| 3 | 172.31.132.0/23 | 172.31.132.0 | 172.31.132.1 | 172.31.133.254 | 172.31.133.255 | 510 |
| 4 | 172.31.134.0/23 | 172.31.134.0 | 172.31.134.1 | 172.31.135.254 | 172.31.135.255 | 510 |
| 5 | 172.31.136.0/23 | 172.31.136.0 | 172.31.136.1 | 172.31.137.254 | 172.31.137.255 | 510 |
| 6 | 172.31.138.0/23 | 172.31.138.0 | 172.31.138.1 | 172.31.139.254 | 172.31.139.255 | 510 |
| 7 | 172.31.140.0/23 | 172.31.140.0 | 172.31.140.1 | 172.31.141.254 | 172.31.141.255 | 510 |
| 8 | 172.31.142.0/23 | 172.31.142.0 | 172.31.142.1 | 172.31.143.254 | 172.31.143.255 | 510 |
| 9 | 172.31.144.0/23 | 172.31.144.0 | 172.31.144.1 | 172.31.145.254 | 172.31.145.255 | 510 |
| 10 | 172.31.146.0/23 | 172.31.146.0 | 172.31.146.1 | 172.31.147.254 | 172.31.147.255 | 510 |
| 11 | 172.31.148.0/23 | 172.31.148.0 | 172.31.148.1 | 172.31.149.254 | 172.31.149.255 | 510 |
| 12 | 172.31.150.0/23 | 172.31.150.0 | 172.31.150.1 | 172.31.151.254 | 172.31.151.255 | 510 |
| 13 | 172.31.152.0/23 | 172.31.152.0 | 172.31.152.1 | 172.31.153.254 | 172.31.153.255 | 510 |
| 14 | 172.31.154.0/23 | 172.31.154.0 | 172.31.154.1 | 172.31.155.254 | 172.31.155.255 | 510 |
| 15 | 172.31.156.0/23 | 172.31.156.0 | 172.31.156.1 | 172.31.157.254 | 172.31.157.255 | 510 |
| 16 | 172.31.158.0/23 | 172.31.158.0 | 172.31.158.1 | 172.31.159.254 | 172.31.159.255 | 510 |