How to compute the network and broadcast of an IPv4 CIDR

1. Enter a CIDR

   "IPv4 CIDR" expects the form `ip/bits` — e.g. `192.168.1.0/24` or `10.0.0.5/16`. The IP doesn't need to be the network address; the tool normalises it for you.

2. Range and validation

   Bits must be 0–32. Each octet of the IP must be 0–255. Anything else throws "Invalid CIDR." or "Invalid IP." — there's no IPv6 support here.

3. Press Run

   Result returns networkAddress (first IP in the block), broadcastAddress (last IP), and usableHosts (2^(32 − bits) − 2; clamped to 0 for /31 and /32).

4. Quick reference

   /24 → 254 usable hosts; /30 → 2 (typical point-to-point link); /32 → 0 (single host); /0 → covers the entire IPv4 internet. For VLSM planning, run the tool multiple times for each subnet.