Network Calculator
Find the network address for any IP address and prefix length. Enter something like 192.168.1.37/24 and this tool instantly returns the network address, subnet mask, wildcard mask and usable host range — all computed locally in your browser.
What Is a Network Address?
The network address is the first address in a subnet and identifies the network itself. It is derived by taking an IP address and a prefix length (the number after the slash in CIDR notation) and setting every host bit to zero. For example, with 192.168.1.37/24, the first 24 bits are the network portion, so the network address is 192.168.1.0. The network address cannot be assigned to a device; it is used by routers to identify the subnet when forwarding traffic.
Calculating the network address is the first step in understanding any IP range. Once you know it, you can derive the subnet mask, the broadcast address, and the range of usable host addresses. This is essential for planning VLANs, configuring routing tables, designing access-control lists, and troubleshooting connectivity between subnets.
How to Use This Tool
- Enter an IP address followed by a prefix length, for example
192.168.1.37/24,10.0.0.5/8or172.16.5.200/25. - Press Calculate (or hit Enter).
- Read the network address in the results table, alongside the subnet mask, wildcard mask and usable host range.
- Use it to verify that an address belongs to the range you expect, or to plan a new subnet.
The calculation runs entirely on your device. Your IP address is never transmitted anywhere, so you can safely work with internal and private ranges without any privacy concern. For the full set of subnet details, including the broadcast address, see the Subnet Calculator.
Network Calculator — Frequently Asked Questions
How do I calculate a network address?
Convert the IP address to a 32-bit number and apply the subnet mask (a run of 1s equal to the prefix length, followed by 0s). The network address is IP AND mask. For 192.168.1.37/24, the mask is 255.255.255.0, so the network address is 192.168.1.0.
What is a prefix length?
The prefix length is the number after the slash in CIDR notation, such as the 24 in 192.168.1.0/24. It tells you how many of the 32 bits in an IPv4 address are fixed as the network portion. A larger prefix means a smaller network: /24 has 8 host bits, while /16 has 16 host bits.
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask. Where the subnet mask has 1s, the wildcard mask has 0s, and vice versa. For a /24 (mask 255.255.255.0), the wildcard mask is 0.0.0.255. Wildcard masks are used in access-control lists (ACLs) to match ranges of addresses.
Can the network address be assigned to a device?
No. The network address is reserved to identify the subnet itself and cannot be assigned to a host. The first usable address is the network address plus one, and the last usable address is one below the broadcast address.
Is this network calculator free and private?
Yes. This tool is completely free and runs entirely in your browser. The calculation is done locally in JavaScript, so the IP address and prefix you enter are never transmitted to any server, logged, or stored.