IPv4 Subnet Calculator
Network address, broadcast, host range, wildcard mask and binary breakdown for any IPv4 CIDR block.
Results for 198.51.100.128/25
198.51.100.128/25 is the network in CIDR notation · Documentation (TEST-NET-2) (RFC 5737)
- Network address
- 198.51.100.128
- Broadcast address
- 198.51.100.255
- Subnet mask
- 255.255.255.128
- Wildcard mask
- 0.0.0.127
- Total addresses
- 128
- Usable hosts
- 126 (excludes network & broadcast)
- First usable host
- 198.51.100.129
- Last usable host
- 198.51.100.254
- CIDR notation
- 198.51.100.128/25
- IP type
- Documentation (TEST-NET-2) (RFC 5737)
How the bits line up
| Octets (binary) | ||||
|---|---|---|---|---|
| IP address | 11000110 | 00110011 | 01100100 | 10000000 |
| Subnet mask | 11111111 | 11111111 | 11111111 | 10000000 |
| Network | 11000110 | 00110011 | 01100100 | 10000000 |
| Broadcast | 11000110 | 00110011 | 01100100 | 11111111 |
The mask's 25 leading ones select the network portion; the remaining 7 bits are available for hosts.
Keep exploring
See every fact about the /25 subnet mask, plan multiple subnets with the VLSM calculator, or convert ranges on the range-to-CIDR tool.