Enter an IPv4 address and prefix length to get the network and broadcast address, subnet and wildcard mask, usable host range, and total and usable host counts.
A subnet is a block of IP addresses. Enter an address and the prefix length (the /24 part) and this tool shows you the whole block: the network address, the broadcast address, the mask, the usable address range, and how many addresses you can actually assign.
Our IP address planning guide covers structured, scalable addressing for ISP networks that survives staff turnover and growth.