Subnet calculator
Subnet Calculator
Enter an IPv4 address with a CIDR prefix (e.g. 192.168.1.0/24) to compute its
network range, subnet mask, and usable hosts.
Network address—
Broadcast address—
Subnet mask—
Wildcard mask—
First usable host—
Last usable host—
Total addresses—
Usable hosts—
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation writes an IP network as an
address followed by a slash and a prefix length — the number of leading bits
that make up the network portion, e.g. 10.0.0.0/16. The remaining bits identify
individual hosts within that network.
Common IPv4 prefixes
| CIDR | Subnet mask | Usable hosts |
|---|---|---|
/24 | 255.255.255.0 | 254 |
/25 | 255.255.255.128 | 126 |
/26 | 255.255.255.192 | 62 |
/27 | 255.255.255.224 | 30 |
/28 | 255.255.255.240 | 14 |
/29 | 255.255.255.248 | 6 |
/30 | 255.255.255.252 | 2 |
Network, broadcast, and usable hosts
Within any subnet of /30 or larger, the first address is the network address (identifies the subnet itself) and the last address is the broadcast address (sends to every host on the subnet). Everything in between is assignable to devices. A /31 is a special two-address case used for point-to-point links, and a /32 identifies a single host.
Example:
192.168.1.0/24 spans 192.168.1.0 –
192.168.1.255 (256 addresses). The network address is
192.168.1.0, the broadcast is 192.168.1.255, and the 254 addresses
in between are usable for hosts.
See also IP lookup, your IPv6 address, or your full public IP overview.