Privacy policy

The controller within the meaning of the GDPR is:

Sidney Thom
Venusstraße 21
12524 Berlin
Deutschland

This policy applies to the app “Formelrechner” (Formula Calculator) and to the website on which this page is published (including /datenschutz, /privacy and /policy). It applies regardless of the device on which the app is used.

There is no user account, no tracking across apps or websites, no advertising, no audience measurement and no analytics cookies. No device advertising identifier is read, and there is no app tracking. Calculations run only on your device. Formula inputs, results, saved lists and device identifiers are not transmitted to Sidney Thom. The app does not access location, contacts, photos, microphone or camera.

The app remembers only locally (device storage or browser localStorage): language, light/dark mode, saved list, recently used formulas and the calculation count. These data do not leave the device unless you use a system backup of the device maker yourself. Legal basis: Art. 6 (1) (f) GDPR (legitimate interest in an app that keeps your settings) or the setting you make yourself. Delete: clear site data, clear app data, or uninstall.

The app works offline. No internet connection is required for calculations, and no telemetry, diagnostics or usage data are sent to us. Where the operator of the app store or of the operating system processes its own data — such as the store account, installation, updates, a payment if you buy the app through the store, and diagnostic or crash reports if you have enabled them in the system — that is its own responsibility under its privacy notices. We do not receive those data and are not the controller for them.

If you open this policy or the web version in a browser, the hosting provider may create server log files (in particular IP address, date and time, page requested, browser type, referrer). This is usual to deliver the page and protect it against abuse (Art. 6 (1) (f) GDPR). We do not use these logs to build profiles, and they are not created by using the app. If a host is in the USA, a transfer may rest on standard contractual clauses or an adequacy decision.

We do not use analytics or advertising cookies in the app or on this website. Technically necessary operations of the host on a mere web visit (section 6) remain unaffected.

Under the GDPR you have the right of access (Art. 15), rectification (Art. 16), erasure (Art. 17), restriction (Art. 18), portability (Art. 20) and objection (Art. 21), and the right to lodge a complaint with a supervisory authority (Art. 77). In Germany this is typically the Berlin Commissioner for Data Protection and Freedom of Information, Alt-Moabit 59–61, 10555 Berlin. Because we do not receive usage data, access in practice is limited to the processes described here. Please send requests to the address above.

Web access is encrypted where HTTPS is used. Absolute security on the internet cannot be guaranteed. The app itself calculates locally and does not transmit your inputs.

Results are a technical aid for training and practice. They do not replace professional verification on site. Users remain responsible for decisions in design, manufacturing or safety.

We will adapt this policy if technology or the law requires it. The version published here applies. Last updated: 28 September 2026.