How to calculate a subnet
- Enter an IPv4 address followed by a slash and a prefix from 0 to 32.
- Read the network, mask, broadcast, and host range below.
- Copy the results for your network notes.
Example: 192.168.1.130/26
This address belongs to network 192.168.1.128/26. Its mask is 255.255.255.192, and its broadcast address is 192.168.1.191. The conventional usable range is 192.168.1.129 through 192.168.1.190, containing 62 hosts.
Understanding /31 and /32
A /31 is treated as a point-to-point link with two usable addresses and no broadcast. A /32 identifies a single host. For prefixes 0 through 30, the network and broadcast addresses are excluded from the conventional usable range. Actual address assignment also depends on network configuration and reserved address ranges.
Input rules and privacy
Use four decimal octets from 0 to 255. Leading zeros, abbreviated addresses, and IPv6 are not accepted. This calculator performs arithmetic only; it does not scan networks or upload your input.