Free network tools
Plan the network.
Keep the details private.
Practical IPv4 planning tools from the team behind Nemesis. Every calculation happens locally in your browser; addresses, VLAN names, and plans are never submitted to us.
IPv4 subnet calculator
Enter any IPv4 address or CIDR to see network boundaries, usable hosts, masks, address scope, and the 32-bit split instantly.
Open calculator →02 / NETWORK PLANNINGVLAN planner
Turn named host requirements into right-sized VLSM allocations, reserve gateways, inspect remaining space, and export the plan.
Open planner →LOCAL-FIRST / BY DESIGN
Nothing to upload. Nothing to retain.
These tools need no account and make no calculation request to a server. Closing the page clears the working plan unless you choose to export it.