Enter an IPv4 address with a CIDR prefix and get the full breakdown of the subnet: network address, broadcast address, usable host range, subnet mask, wildcard mask and the total number of addresses. Subnetting math is easy to get wrong under pressure, and one off-by-one on the host range can mean a misconfigured firewall rule or a wasted afternoon. This calculator does the bitwise work for you and lays out every value you typically need when planning address space or reading a network diagram. Type something like 192.168.1.10/24 and read off the results. All calculations happen in your browser with no lookups, so your addressing plans stay entirely private.