Miroslav Hanzelka created the Project Planet app and website as a free service. This SERVICE is provided by Miroslav Hanzelka at no cost and is intended for use as is.

This page is used to inform visitors regarding my policies with the collection, use, and disclosure of Personal Information if anyone decides to use my Service.

If you choose to use my Service, then you agree to the collection and use of information in relation to this policy. The Personal Information that I collect is used for providing and improving the Service. I will not use or share your information with anyone except as described in this Privacy Policy.

The terms used in this Privacy Policy have the same meanings as in our Terms and Conditions, which are accessible at Project Planet unless otherwise defined in this Privacy Policy.

Information Collection and Use

Project Planet recalculates your weight and age across the planets of the solar system. To do that the app may ask you for your weight and age. This information is stored only in your browser (local storage) and is never transmitted to me or to any server. You can clear it at any time using the "Clear data" button in the app or by clearing your browser data.

Local Storage and Cookies

The app saves a small amount of data on your device so the experience can pick up where you left off. Specifically:

• projectplanet:settings — your weight, age, and metric/imperial preference.
• pp_last_seen_version — the app version you last visited so we can show changelog highlights on return.
• pp_lang_prompt_dismissed — a flag so we don’t repeatedly ask whether you want to switch language.
• NEXT_LOCALE cookie — your selected language so the site loads in the right locale on subsequent visits.

No third-party tracking cookies are set by the app itself. Your browser language (navigator.language) is read on the client only to suggest a matching translation and is never transmitted off your device.

Analytics

The website uses Umami, a privacy-focused, self-hosted analytics tool. Umami does not use cookies, does not store full IP addresses, and does not build cross-site profiles. It records aggregate page-view statistics so I can understand which planets people scroll to most. The analytics instance is operated by me on my own infrastructure.

In addition to page views, the site records anonymous interaction events — for example which planet you reached, which calculator you opened, whether you toggled between metric and imperial, or whether you used the share button. These events contain no personal data: the weight and age values you enter are never sent. Only short identifiers (planet name, widget name, locale) and boolean flags (e.g. whether a value was entered) are recorded so I can see which parts of the site people find most useful.

Languages

The site is available in Czech, English, German, Slovak, Spanish and French. The first time you visit, the locale is selected from your browser language (read locally) or the URL path (e.g. /cs, /de). You can switch at any time using the language switcher in the page. Your choice is remembered via the NEXT_LOCALE cookie described above.

iOS App

When the website is accessed through the Project Planet iOS app, the app embeds the same web experience in a system WebView. The native shell adds haptic feedback to small UI interactions through Apple’s standard WebKit bridge. The iOS shell does not collect additional personal data beyond what the website itself uses.

Log Data

Whenever you use my Service, basic server-level logs may be recorded by the hosting provider (e.g. request timestamps, IP address, user agent) for the purpose of operating, securing and debugging the Service. This Log Data is short-lived and is not combined with your Personal Information.

Service Providers

I may employ third-party companies and individuals to:

• Host the website (currently Vercel).
• Provide the privacy-focused analytics described above (self-hosted Umami).
• Assist with bug investigation and performance monitoring when needed.

These providers may have access to information necessary to perform their tasks but are obligated not to disclose or use it for any other purpose.

Security

I value your trust in providing me your Personal Information, and I strive to use commercially acceptable means of protecting it. But remember that no method of transmission over the internet, or method of electronic storage, is 100% secure, and I cannot guarantee its absolute security.

Links to Other Sites

This Service may contain links to other sites. If you click on a third-party link, you will be directed to that site. Note that these external sites are not operated by me. I strongly advise you to review the Privacy Policy of any websites you visit. I have no control over and assume no responsibility for the content, privacy policies, or practices of any third-party sites or services.

Children’s Privacy

Project Planet is suitable for general audiences, including children. The app does not intentionally collect personally identifiable information from anyone — the weight and age inputs described above never leave the device. If you are a parent or guardian and you have any concerns, please contact me.

Changes to This Privacy Policy

I may update this Privacy Policy from time to time. You are advised to review this page periodically. I will notify you of any changes by posting the new Privacy Policy on this page.

This policy is effective as of 2026-05-12.

Contact Us

If you have any questions or suggestions about my Privacy Policy, do not hesitate to contact me at Project Planet.