Calculations & Files
Calculations, subnet plans and CSV imports are processed in your browser. The application does not upload their contents. CSV, Excel and JSON downloads are generated on your device.
Saved Plans & Browser Storage
Plans are saved in this browser on this device, without an account or cloud synchronization. The site also stores your theme preference, active-plan selection and an offline copy of the application.
Deleting a plan removes its saved browser copy. Clearing this site’s browser data removes saved plans and preferences; downloaded backups remain in your files. Export a JSON backup before clearing site data or moving to another browser.
Hosting & Request Data
Cloudflare hosts the site and handles its security and delivery. It may process request information such as your IP address, browser details, requested URLs and timestamps. The application does not add advertising trackers or send calculation and plan contents in those requests.
Cloudflare may use cookies or similar mechanisms for security. Its privacy policy (opens in a new tab) describes its data handling.
Visitor & Performance Analytics
On cidr.sh, Cloudflare Web Analytics measures page views, referral sources and page performance. Its browser beacon sends technical measurements to Cloudflare, including page paths, browser and device information, and loading timings. Cloudflare states that Web Analytics does not use cookies, local storage or fingerprinting to track visitors, and does not collect URL query strings.
We do not add calculation inputs, subnet addresses, plan names, imported files or DNS settings to analytics events or URLs. Cloudflare’s script runs in the page; it is not part of the offline application cache. Browser blocking and offline use can prevent measurement. See Cloudflare’s Web Analytics documentation (opens in a new tab) for its collection practices.
Browser Integrations
In a compatible browser, assistant tools can read the active plan, calculate subnets and stage allocation previews. If you use these tools, your browser or assistant provider may process the information under its own privacy settings. Applying an allocation preview still requires confirmation in the site.
External Links
Provider documentation and other external links open third-party sites with their own privacy practices.