CIDR Calculator
Calculate CIDR block details
Source Input
Processed Output
What is the CIDR Calculator?
CIDR notation (e.g. 10.0.0.0/8) compactly describes an IP range. This calculator converts CIDR to dotted-decimal masks, computes the network and broadcast addresses, lists the usable host range, and counts available addresses — essential for VPC design, firewall rules, and access control lists.
Frequently Asked Questions (FAQ)
Q: How are usable hosts calculated?
Total addresses minus 2 (network and broadcast). The /31 and /32 exceptions used for point-to-point links are handled correctly.
How to Use the CIDR Calculator
- 1Paste your input into the editor above — or start from the preloaded example.
- 2Adjust any options, then click Run to process instantly in your browser.
- 3Review the output panel, then copy, download, or save it as a reusable snippet.