IP and CIDR Subnet Calculator
Enter an IP address and prefix length to get the network, broadcast, mask and usable host range.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
IP and CIDR Subnet Calculator
How to use this tool
- Enter your values in the fields above.
- Press Generate to see the result.
- Use Load sample to try the worked example, Copy result to copy it, or Clear to start again.
Worked example
192.168.1.10/24 gives network 192.168.1.0, broadcast 192.168.1.255, mask 255.255.255.0, usable range 192.168.1.1 to 192.168.1.254, and 254 usable hosts.
What this tool does not do / Limits
This tool only does subnet arithmetic on the address you type. It does not look up, scan or test any live network or device.
Frequently asked questions
What is the usable range?
The addresses between the network and broadcast addresses, which are the ones normally assigned to hosts.
Does /31 have usable hosts?
Yes, both addresses in a /31 are shown as usable, and a /32 is a single host address.
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