CIDR to Subnet Mask Calculator
Bidirectional converter between CIDR prefix notation (/24) and dotted-decimal subnet masks.
Subnet Mask: 255.255.255.0
Wildcard Mask: 0.0.0.255
Total IPs: 256
Usable Hosts: 254
How It Works
- Translates prefix length into contiguous 32-bit subnet mask.
Formula & Technical Standard
Subnet Mask Octet = Sum of active bits in octet.
Practical Example
Prefix /28
Input: /28
Output: 255.255.255.240 | 14 Usable Hosts
4-bit host space yields 2^4 = 16 total IPs.
Frequently Asked Questions
What is a wildcard mask?
The bitwise inverse of a subnet mask (~mask), used in Cisco ACLs.
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