Network Tools
1 free network tool, all running privately in your browser.
These free network tools help with IP and subnet math - calculating subnet masks, usable host counts, network and broadcast addresses, and CIDR ranges. Each computes results instantly in your browser, with a reference table to explain the notation.
Subnetting trips up even experienced engineers because it's binary math done under time pressure. A calculator that shows the mask, host range, and CIDR notation together removes the arithmetic errors. The subnet calculator includes a CIDR reference so you can sanity-check any block at a glance.
Frequently asked questions
How many hosts does a /24 subnet have?
A /24 has 256 total addresses and 254 usable hosts - the all-zeros address names the network and the all-ones address is the broadcast address, so both are reserved.