100.91.0.0/25
PublicClass A — /25 prefix — 126 usable hosts
Network address — the base address of the block (100.91.0.0). All devices in this subnet share this prefix. Cannot be assigned to a host.
Broadcast address — packets sent to 100.91.0.127 are delivered to every device in the subnet. Also reserved — not assignable.
Usable hosts — the 126 addresses between those two that you can assign to servers, VMs, or interfaces.
Subnet mask — 255.255.255.128 is the dotted-decimal equivalent of /25. Older tools and Cisco configs use this format instead of CIDR slash notation.
Full Details
| CIDR Notation | 100.91.0.0/25 |
| Network Address | 100.91.0.0 |
| Broadcast Address | 100.91.0.127 |
| Subnet Mask | 255.255.255.128 |
| Wildcard Mask | 0.0.0.127 |
| Prefix Length | /25 |
| IP Address Class | Class A |
| Total IP Addresses | 128 |
| Usable Host Addresses | 126 |
| First Usable IP | 100.91.0.1 |
| Last Usable IP | 100.91.0.126 |
| Network (Hex) | 0x645B0000 |
| Broadcast (Hex) | 0x645B007F |
| Address Type | Public / Globally Routable |
Binary Representation
The first 25 bits (1s in the mask) identify the network. The remaining 7 bits identify hosts within the network.
Split into Equal Subnets
Split 100.91.0.0/25 into 2 equal /26 subnets (62 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 100.91.0.0/26 | 100.91.0.0 | 100.91.0.1 | 100.91.0.62 | 100.91.0.63 | 62 |
| 2 | 100.91.0.64/26 | 100.91.0.64 | 100.91.0.65 | 100.91.0.126 | 100.91.0.127 | 62 |
Split 100.91.0.0/25 into 4 equal /27 subnets (30 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 100.91.0.0/27 | 100.91.0.0 | 100.91.0.1 | 100.91.0.30 | 100.91.0.31 | 30 |
| 2 | 100.91.0.32/27 | 100.91.0.32 | 100.91.0.33 | 100.91.0.62 | 100.91.0.63 | 30 |
| 3 | 100.91.0.64/27 | 100.91.0.64 | 100.91.0.65 | 100.91.0.94 | 100.91.0.95 | 30 |
| 4 | 100.91.0.96/27 | 100.91.0.96 | 100.91.0.97 | 100.91.0.126 | 100.91.0.127 | 30 |
Split 100.91.0.0/25 into 8 equal /28 subnets (14 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 100.91.0.0/28 | 100.91.0.0 | 100.91.0.1 | 100.91.0.14 | 100.91.0.15 | 14 |
| 2 | 100.91.0.16/28 | 100.91.0.16 | 100.91.0.17 | 100.91.0.30 | 100.91.0.31 | 14 |
| 3 | 100.91.0.32/28 | 100.91.0.32 | 100.91.0.33 | 100.91.0.46 | 100.91.0.47 | 14 |
| 4 | 100.91.0.48/28 | 100.91.0.48 | 100.91.0.49 | 100.91.0.62 | 100.91.0.63 | 14 |
| 5 | 100.91.0.64/28 | 100.91.0.64 | 100.91.0.65 | 100.91.0.78 | 100.91.0.79 | 14 |
| 6 | 100.91.0.80/28 | 100.91.0.80 | 100.91.0.81 | 100.91.0.94 | 100.91.0.95 | 14 |
| 7 | 100.91.0.96/28 | 100.91.0.96 | 100.91.0.97 | 100.91.0.110 | 100.91.0.111 | 14 |
| 8 | 100.91.0.112/28 | 100.91.0.112 | 100.91.0.113 | 100.91.0.126 | 100.91.0.127 | 14 |
Split 100.91.0.0/25 into 16 equal /29 subnets (6 usable hosts each).
| # | CIDR | Network | First Usable | Last Usable | Broadcast | Hosts |
|---|---|---|---|---|---|---|
| 1 | 100.91.0.0/29 | 100.91.0.0 | 100.91.0.1 | 100.91.0.6 | 100.91.0.7 | 6 |
| 2 | 100.91.0.8/29 | 100.91.0.8 | 100.91.0.9 | 100.91.0.14 | 100.91.0.15 | 6 |
| 3 | 100.91.0.16/29 | 100.91.0.16 | 100.91.0.17 | 100.91.0.22 | 100.91.0.23 | 6 |
| 4 | 100.91.0.24/29 | 100.91.0.24 | 100.91.0.25 | 100.91.0.30 | 100.91.0.31 | 6 |
| 5 | 100.91.0.32/29 | 100.91.0.32 | 100.91.0.33 | 100.91.0.38 | 100.91.0.39 | 6 |
| 6 | 100.91.0.40/29 | 100.91.0.40 | 100.91.0.41 | 100.91.0.46 | 100.91.0.47 | 6 |
| 7 | 100.91.0.48/29 | 100.91.0.48 | 100.91.0.49 | 100.91.0.54 | 100.91.0.55 | 6 |
| 8 | 100.91.0.56/29 | 100.91.0.56 | 100.91.0.57 | 100.91.0.62 | 100.91.0.63 | 6 |
| 9 | 100.91.0.64/29 | 100.91.0.64 | 100.91.0.65 | 100.91.0.70 | 100.91.0.71 | 6 |
| 10 | 100.91.0.72/29 | 100.91.0.72 | 100.91.0.73 | 100.91.0.78 | 100.91.0.79 | 6 |
| 11 | 100.91.0.80/29 | 100.91.0.80 | 100.91.0.81 | 100.91.0.86 | 100.91.0.87 | 6 |
| 12 | 100.91.0.88/29 | 100.91.0.88 | 100.91.0.89 | 100.91.0.94 | 100.91.0.95 | 6 |
| 13 | 100.91.0.96/29 | 100.91.0.96 | 100.91.0.97 | 100.91.0.102 | 100.91.0.103 | 6 |
| 14 | 100.91.0.104/29 | 100.91.0.104 | 100.91.0.105 | 100.91.0.110 | 100.91.0.111 | 6 |
| 15 | 100.91.0.112/29 | 100.91.0.112 | 100.91.0.113 | 100.91.0.118 | 100.91.0.119 | 6 |
| 16 | 100.91.0.120/29 | 100.91.0.120 | 100.91.0.121 | 100.91.0.126 | 100.91.0.127 | 6 |
IP Address Sample
Showing first 16 of 128 total IPs.