Working out a network's address range from an IP and CIDR prefix by hand involves binary math that's easy to get wrong — this calculator handles the conversion instantly for standard IPv4 addressing.
Enter any IPv4 address and CIDR prefix length (like /24), and the tool calculates the network address, broadcast address, subnet mask, and the number of usable host addresses within that subnet.
This is useful for network administrators planning IP address allocation, students learning subnetting, or anyone troubleshooting a network configuration who needs to quickly verify which addresses fall within a given subnet.
Because everything runs locally in your browser, results appear instantly and nothing you type or upload is ever sent to a server.
Bookmark this page if you expect to use this tool regularly — it loads fast and behaves the same way every time, with no account needed.
This kind of task shows up constantly in everyday writing, coding, design, and admin work, which is exactly why a dedicated, focused tool saves so much back-and-forth.
A tool that does one job well, without a cluttered interface or unrelated features competing for attention, tends to be faster to use than a heavier all-in-one app.
If you find yourself needing this often, keeping this page open in a tab is usually faster than digging through a bigger software suite's menus.
Frequently asked questions
What does /24 mean?
It's CIDR notation indicating the first 24 bits of the 32-bit IP address are the network portion, leaving 8 bits for host addresses — equivalent to a 255.255.255.0 subnet mask.
Why is usable hosts always 2 less than the total addresses in the subnet?
The first address in any subnet is reserved as the network address and the last as the broadcast address, so both are excluded from the usable host range.