IP Range Calculator
Convert IP ranges to CIDR and back
Source Input
Processed Output
What is the IP Range Calculator?
Firewalls and cloud security groups often need CIDR blocks, but humans think in start/end ranges. This calculator converts any IP range into the minimal set of CIDR blocks covering it exactly (no more, no less) — the same summarization routers perform for route aggregation.
Frequently Asked Questions (FAQ)
Q: Why does one range become multiple CIDRs?
CIDR blocks must align to power-of-two boundaries, so arbitrary ranges need several aligned blocks to be represented exactly.
How to Use the IP Range 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.