Subnet calculator
Enter an IPv4 address in CIDR notation, for example
192.168.1.130/26, and get the network, broadcast, usable
range and masks. Everything runs in your browser; nothing is sent
anywhere.
How to read the result
The network address identifies the subnet itself and the broadcast address is the last address in it; neither can be assigned to a host, which is why usable hosts is the total minus two. The exceptions are /31 (both addresses usable, point-to-point links per RFC 3021) and /32 (a single host route).
The wildcard mask is the bitwise inverse of the netmask, used by router and firewall ACLs.
If you want the maths behind the numbers, the companion post covers it: IPv4 subnet cheat sheet: every mask, and the maths behind it.
Subnet mismatches across a fleet?
Moorfox inventories every managed machine's interfaces with address, gateway, DNS and DHCP state, so the odd one out shows up in a list instead of in a ticket.