How to use the Subnet Calculator
Use this calculator to find the network that contains an IP address when you know its prefix length or IPv4 dotted subnet mask.
- Enter the device or interface IP address.
- Enter a prefix such as /24 or an IPv4 mask such as 255.255.255.0.
- Compare the calculated network, address range, and host range with the device, gateway, DHCP scope, and route configuration.
How to read the result
The IP and mask combine to produce one containing network. Addresses in that range are usually reached through the connected route; other destinations need a more specific route or a gateway.
Example
- Input
192.168.1.37 with /24- What to look for
- The address belongs to 192.168.1.0/24, whose ordinary IPv4 host range is 192.168.1.1 through 192.168.1.254.
Before you act on the result
Matching arithmetic does not prove that two devices share a VLAN, that a gateway is configured correctly, or that routing and firewall policy permit packets to pass.
Read the Subnet Calculator Guide for the technology overview and troubleshooting steps.