Network Address Calculator
Determine the network address of a subnet from an IP address and mask or prefix length.
Inputs
Network Address
10.45.64.0
Subnet Mask
255.255.240.0
Step by step
Subnet mask from prefix
/20
= 255.255.240.0
AND operation
10.45.67.89 AND 255.255.240.0
= 10.45.64.0
How it works
The network address is found by performing a bitwise AND between the IP address and its subnet mask. This zeroes out the host bits, leaving only the network portion — the identifier for the subnet itself.
Formula
Network address
network = IP AND subnet_mask
- IP
- Any host IP in the subnet
- M
- Subnet mask
Frequently Asked Questions
Is the network address usable as a host address?
No — the network address (all host bits zero) identifies the subnet itself and cannot be assigned to a host in standard subnetting. The exception is /31 point-to-point links per RFC 3021.
How is the network address used in routing?
Routers store network addresses (with their prefix lengths) in routing tables to determine which interface or next-hop to forward packets toward for any destination within that network.