What is a Network Address?
The network address (also called Network ID) is the first address in a subnet and identifies the network itself. It's calculated by performing a bitwise AND operation between an IP address and its subnet mask. All devices on the same network share the same network address, which routers use to make forwarding decisions.
For example, if your computer has IP 192.168.1.100 with subnet mask 255.255.255.0, the network address is 192.168.1.0. Any other device with an IP in the range 192.168.1.1-254 and the same mask will have the same network address and can communicate directly without routing. For complete subnet information, use our subnet calculator.
Key Point
The network address cannot be assigned to any host device. It's reserved to identify the network in routing tables. The last address (broadcast) is also reserved, leaving all addresses in between for host assignment.
How Network Address is Calculated
The network address is calculated using a bitwise AND operation between the IP address and subnet mask:
Calculation Example
IP Address: 192.168.1.100
Subnet Mask: 255.255.255.0
Binary AND:
IP: 11000000.10101000.00000001.01100100
Mask: 11111111.11111111.11111111.00000000
─────────────────────────────────────
AND: 11000000.10101000.00000001.00000000
Network Address: 192.168.1.0
Why Network Address Matters
Routing Decisions
Routers use network addresses to determine where to forward packets. When a device sends data, the router compares the destination's network address with entries in its routing table to find the best path.
Network Segmentation
Network addresses define subnet boundaries. Devices with the same network address can communicate directly (Layer 2), while devices with different network addresses require a router (Layer 3).
Troubleshooting Connectivity
When two devices can't communicate, checking if they share the same network address is a fundamental troubleshooting step. If they have different network addresses, they need proper routing configured.
Network Address vs Other Addresses
| Address Type | Example (/24) | Purpose | Assignable? |
|---|---|---|---|
| Network Address | 192.168.1.0 | Identifies the network | No |
| First Host | 192.168.1.1 | First assignable address | Yes |
| Last Host | 192.168.1.254 | Last assignable address | Yes |
| Broadcast | 192.168.1.255 | Send to all hosts | No |
To calculate the broadcast address, use our broadcast address calculator. For comprehensive subnet details, the CIDR calculator provides all addresses in one view.
Determining If Two IPs Are on the Same Network
To check if two IP addresses are on the same network, calculate the network address for each using the same subnet mask. If the network addresses match, the IPs are on the same subnet.
Same Network Check
IP 1: 192.168.1.50 with /24 → Network: 192.168.1.0
IP 2: 192.168.1.200 with /24 → Network: 192.168.1.0
Result: Same network ✓ (can communicate directly)
IP 1: 192.168.1.50 with /24 → Network: 192.168.1.0
IP 2: 192.168.2.50 with /24 → Network: 192.168.2.0
Result: Different networks ✗ (require router)
Use our IP subnet calculator to analyze multiple addresses. For a visual representation of network divisions, try the visual subnet calculator.