Address planning/ 01
Subnet calculator
Break down any IPv4 address into its network, host range, and binary boundaries.
Network input
Start with an IPv4 address.
Four decimal octets followed by /0–/32.
Try an example
Calculations update as you type. Host bits in the input are preserved; the network address is calculated separately.
Subnet details
- IP address
- 192.168.1.20
- Network / CIDR
- 192.168.1.0/24
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- Network address
- 192.168.1.0
- Broadcast address
- 192.168.1.255
- First usable host
- 192.168.1.1
- Last usable host
- 192.168.1.254
- Address type
- Private · RFC 1918
- Historical IP class
- C
CIDR prefix/248 host bits
Total addresses2562^8 address space
Usable hosts254Network & broadcast excluded
Under the mask
The prefix separates network bits from host bits.
IP address24 network 8 host
11000000
Octet 110101000
Octet 200000001
Octet 300010100
Octet 4Subnet mask24 network 8 host
11111111
Octet 111111111
Octet 211111111
Octet 300000000
Octet 4Usable capacity excludes network and broadcast addresses. Address classification refers to the input IP; it does not guarantee routability of the entire block.