IPv4 Subnet Calculator
Network address, broadcast, host range, wildcard mask and binary breakdown for any IPv4 CIDR block.
Results for 198.51.100.4/31
198.51.100.4/31 is the network in CIDR notation · Documentation (TEST-NET-2) (RFC 5737)
- Network address
- 198.51.100.4
- Broadcast address
- 198.51.100.5
- Subnet mask
- 255.255.255.254
- Wildcard mask
- 0.0.0.1
- Total addresses
- 2
- Usable hosts
- 2 (point-to-point per RFC 3021)
- First usable host
- 198.51.100.4
- Last usable host
- 198.51.100.5
- CIDR notation
- 198.51.100.4/31
- IP type
- Documentation (TEST-NET-2) (RFC 5737)
How the bits line up
| Octets (binary) | ||||
|---|---|---|---|---|
| IP address | 11000110 | 00110011 | 01100100 | 00000100 |
| Subnet mask | 11111111 | 11111111 | 11111111 | 11111110 |
| Network | 11000110 | 00110011 | 01100100 | 00000100 |
| Broadcast | 11000110 | 00110011 | 01100100 | 00000101 |
The mask's 31 leading ones select the network portion; the remaining 1 bits are available for hosts.
Keep exploring
See every fact about the /31 subnet mask, plan multiple subnets with the VLSM calculator, or convert ranges on the range-to-CIDR tool.