Enter an IPv4 address and a prefix length to get the network, broadcast, netmask and usable host range for that subnet.
The calculator masks the address with the chosen prefix length to find the network address, then derives the broadcast address, netmask and wildcard mask from the same mask. Total addresses are 2 raised to the power of the remaining host bits. Usable hosts normally exclude the network and broadcast addresses; a /31 link has two usable addresses under the point-to-point convention, and a /32 is a single host route. The class is read from the first octet, and the private check covers the RFC 1918 ranges, loopback and link-local space.
What is the difference between total and usable addresses? The total counts every address in the block, including the network address and the broadcast address. The usable count excludes those two on normal subnets, which is why a /24 has 256 total addresses but 254 usable hosts.
What do /31 and /32 mean? A /31 leaves two addresses and is used on point-to-point links, where both can be assigned. A /32 leaves one address and describes a single host route.
Is 192.168.x.x a private address? Yes. 192.168.0.0/16 is one of the RFC 1918 private ranges, along with 10.0.0.0/8 and 172.16.0.0/12. Private addresses are not routed on the public internet.