Free Networking Tools
Free interactive networking tools — a subnet calculator, VLSM planner, binary converter and Cisco command lookup. Everything runs in your browser; nothing is sent to any server. Bookmark this page for daily use.
IPv4 Subnet Calculator
Enter an IP address and prefix — get network, broadcast, host range, subnet mask, wildcard mask and binary, instantly. Open the full subnet calculator →
VLSM Calculator
Enter a base network and the hosts each subnet needs (comma-separated) — get an efficient VLSM allocation. Open the full VLSM calculator →
Binary ⇆ Decimal Converter
Convert numbers or full IPv4 addresses between decimal and binary. Open the full binary converter →
Cisco Command Lookup
Search the commands every CCNA student must know — what they do and which mode they run in.
Want to master these for real?
Calculators build speed — real skill comes from configuring actual routers and switches. That's how we train.