Enter an address in CIDR notation and get the network address, broadcast address, subnet mask, wildcard mask and the usable host range — including the /31 and /32 edge cases most calculators get wrong.
Runs entirely in your browser
Subnetting is the arithmetic of dividing an IP network into smaller pieces, and getting it wrong leads to overlapping ranges, wasted addresses and hosts that cannot talk to each other. This calculator takes an IPv4 address in CIDR notation — like 192.168.1.0/24 — and works out everything that follows from it: the network address, the broadcast address, the subnet mask and its wildcard mask, and the range of usable host addresses.
It handles the edge cases many calculators get wrong. A /31 is treated as a two-address point-to-point link rather than a network with no usable hosts, and a /32 is recognised as a single-host route. Those distinctions matter in real configurations — router links and host routes both rely on them — so the tool reflects how the addresses are actually used.
It is a fast reference whether you are planning an address scheme, reading a firewall rule, or sanity-checking a configuration. Because it runs in your browser, you can work through internal addressing without sending any of your network layout to a server.
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