Convert between CIDR prefix length, subnet mask and wildcard mask for IPv4 networks.
-Prefix
-Subnet mask
-Wildcard
For beginners: how to read the result
Start with the first cardIt gives the direct answer for the current mode before the longer output text.
Use the output boxCopy the exact converted value, table, header or parsed data from the output area.
Keep sensitive data localThe calculator runs in your browser, but you should still avoid secrets that your policy forbids in tools.
Paste your value, choose the mode if the calculator has one, and use the first result card as the direct answer. The longer output area is designed for copying into code, documentation, API tests or a spreadsheet.
What the result means
The wildcard mask is the inverse of the subnet mask and is often used in firewall and routing examples.
What is not included
The input must be a prefix from /0 to /32 or a valid dotted IPv4 mask.
Privacy note
The interactive calculation runs in your browser. The page still should not be used with passwords, tokens or personal data that your own rules do not allow in browser tools.