What it does
Jodies ipcalc calculates network, broadcast, wildcard and host-range values from an IP address and mask, with a second mask for subnet planning.
Give Jodies ipcalc an IPv4 address and an explicit mask in CIDR or dotted-decimal form. It calculates network, broadcast, host range and Cisco-style wildcard values, with binary spacing showing the network and host bits. A second mask explores subnetting or supernetting. Enter the mask deliberately: leaving it blank selects a class-based default, which can be wrong for the intended CIDR network. This is address arithmetic, not a reachability or allocation-authority check. The site also offers a shell utility, but labels the web example 0.35.2 and points to 0.41 in its archive, so match options to the version used.
Strengths
- Binary explanation of subnet boundaries
Best for
- Learning and checking IPv4 subnet calculations
Sources
- IP Calculator / IP Subnetting (Oct 26, 2026)