Subnet Calculator (CIDR)
Enter an IPv4 address with CIDR prefix (e.g. 192.168.1.0/24) to calculate its network details.
How it works
CIDR notation (/24) specifies how many leading bits of the 32-bit IPv4
address are the network portion. The netmask is derived from the prefix, the network
address is the input address with all host bits set to 0, and the broadcast address is
the same with all host bits set to 1. Usable hosts exclude the network and broadcast
addresses (except for /31 and /32, which have no usable range).
Examples
| CIDR | Network | Broadcast | Usable hosts |
|---|---|---|---|
192.168.1.0/24 | 192.168.1.0 | 192.168.1.255 | 254 |
10.0.5.130/26 | 10.0.5.128 | 10.0.5.191 | 62 |
192.168.1.5/32 | 192.168.1.5 | 192.168.1.5 | 0 |
FAQ
What if my address isn't the network address? No problem — any host address within the subnet works as input; it's normalized down to the network address.
What about /0 or /32? Both are valid edge cases: /0
covers the entire address space, /32 covers a single host with no usable
range.