Free tool
NetworkingNetwork Address Calculator
Free network address calculator for CCNA and IT students. Enter an IPv4 address and mask or CIDR to find the network ID, and see how it differs from host addresses.
Runs in your browser — your data stays on your device
Free toolThe network address, also called the network ID, identifies the subnet itself. You never assign it to a PC or printer, yet every route, ACL, and DHCP scope depends on getting it right. This free network address calculator takes any host IP plus a CIDR prefix or subnet mask and returns the network ID immediately, along with enough context to show whether the address you typed is the network, the broadcast, or a usable host. That check stops a mistake we see constantly in beginner labs: students configure a gateway on .0 and wonder why the interface rejects it.
How to use the Network Address Calculator
- 1
Enter any IPv4 address that belongs to the subnet, for example 192.168.1.37.
- 2
Enter the CIDR prefix or dotted mask, such as /24 or 255.255.255.0.
- 3
Read the network address first, then confirm whether your input was a host, the network ID, or the broadcast.
Why finding the network ID matters
Routing entries point at networks, not at random hosts. If you miscalculate the network address from CIDR, static routes and OSPF network statements land on the wrong block. Home networks hide this because consumer routers do the maths for you. On CCNA labs and in network administration work, you must derive the network ID from an IP and mask by hand, then confirm with a tool before you trust the config.
IPv4 network address example
Take 172.16.8.15 with mask 255.255.255.240 (/28). The calculator returns network address 172.16.8.0, broadcast 172.16.8.15, and 14 usable hosts. Notice the address you typed is the broadcast in this case, a useful warning before you try to assign .15 to a server.
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