Network Details
How IPv4 Subnetting Works
Subnetting is the practice of dividing a large network into smaller, more manageable networks. An IPv4 address is 32 bits long, divided into a network portion and a host portion. The CIDR (Classless Inter-Domain Routing) notation, such as /24, tells you exactly how many bits are assigned to the network portion.
For example, a /24 mask means the first 24 bits are fixed (the network), leaving the remaining 8 bits for individual devices (hosts), which mathematically allows for 254 usable IPs.
Subnet Calculator FAQ
Why are there 2 fewer usable hosts than total IPs?
In any standard IPv4 subnet, the very first IP address is reserved to identify the network itself (Network Address), and the very last IP address is reserved for sending messages to all devices on that network (Broadcast Address). Therefore, the formula for usable hosts is always 2^(host bits) - 2.
How are the subnet details calculated?
Our calculator relies on mathematical bitwise operations executed entirely by client-side JavaScript within your browser. Because the processing happens locally on your device, the network data and IP addresses you enter are never transmitted to or logged by our servers.