Privacy Policy

1. Who we are

Subnet Calculator ("we", "us", the "Service") is a free online tool for calculating IPv4 and IPv6 subnets, splitting blocks with VLSM, and summarizing CIDR ranges. This policy explains what information is and isn't handled when you use it.

2. The data you enter stays on your device

Every calculation: network and broadcast addresses, host ranges, subnet and wildcard masks, VLSM allocations and CIDR aggregation, is performed locally in your browser using JavaScript. The IP addresses, prefixes and networks you type are never sent to us or to any server. There is no backend that receives or processes your inputs.

3. Local storage

We use your browser's local storage for one purpose only: to remember your light or dark theme preference (under the key subnetcalc-theme) so the site looks the way you left it. This value stays on your device, is not a cookie, and is not transmitted anywhere. You can clear it at any time through your browser settings.

4. Shareable links

For convenience, the current state of the calculator is encoded into the page's URL (the part after the ?). This lets you bookmark or share a calculation. That information only leaves your device if you choose to copy and share the link, for example by sending it to a colleague. If you do, be aware that the networks in the URL will be visible to whoever receives it.

5. No cookies, no tracking, no ads

We do not set advertising or tracking cookies, we do not run third-party analytics that profile you, and we do not sell data. Because we don't collect it in the first place.

6. Hosting and server logs

The site is delivered as static files by our hosting provider's global content-delivery network. Like virtually all web hosts, the provider may automatically process standard technical request metadata (such as your IP address, browser type and the time of the request) to serve the files, ensure security and prevent abuse. This is handled by the hosting provider under their own terms and is not combined with anything you calculate.

7. Children's privacy

The Service is a general-audience utility and is not directed at children. Because we collect no personal information, we do not knowingly process any data from children.

8. Your rights

Since we do not collect or store personal data about you, there is no personal data for us to access, correct or delete. Any information the site uses (your theme preference, your current inputs) lives on your own device and is fully under your control.

9. Changes to this policy

We may update this policy from time to time, for example if we add new features. When we do, we'll revise the "last updated" date above. Continued use of the Service after a change means you accept the revised policy.

10. Contact

Questions about this policy? Please reach out via our Contact Us page. See also our Terms & Conditions.