IPv4 Subnet Calculator
Analyze any IPv4 address and CIDR prefix: network address, broadcast, usable host range, subnet mask, wildcard mask and total hosts. Essential for firewall, VLAN and infrastructure planning.
Type an address like 192.168.1.0/24 or pick a prefix length, and the calculator derives the full network geometry plus a quick reference of neighboring blocks.
CIDR input
256 total addresses · 254 usable /24
Subnet details
- Network address
192.168.1.011000000.10101000.00000001.00000000 - Broadcast address
192.168.1.25511000000.10101000.00000001.11111111 - Subnet mask
255.255.255.011111111.11111111.11111111.00000000 - Wildcard mask
0.0.0.25500000000.00000000.00000000.11111111 - First usable host
192.168.1.1 - Last usable host
192.168.1.254
A /31 or /32 is treated as a point-to-point link, where the network address itself is usable, matching the convention in RFC 3021. First is192.168.1.1and last is192.168.1.254.
Frequently asked questions
What is a /24 network?
A /24 uses 24 bits for the network portion, leaving 8 host bits: 256 addresses, 254 usable on most networks.
Which addresses are not host-usable?
The network address (all host bits zero) and the broadcast address (all host bits one) are reserved on most networks.