CIDR / Netmask Converter

Translate an IPv4 CIDR prefix into dotted netmask, wildcard mask and binary form.

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About this tool

What is CIDR / Netmask Converter?

CIDR / Netmask Converter translates a prefix length into dotted, wildcard and binary IPv4 mask forms.

Three simple steps

01
Enter a CIDR prefix from 0 to 32.
02
Compare the host-bit and total-address impact of nearby prefixes.
03
Copy the mask representation required by your router, firewall or documentation.

Common questions

Is /24 always 255.255.255.0?

Yes. A /24 prefix sets the first 24 mask bits, producing 255.255.255.0 and 256 total addresses.

Is CIDR / Netmask Converter private to use?

Yes. Address and network calculations use only the values entered in your browser and do not probe external systems.