Last updated: June 5, 2026
Kalc is a mobile mental math training app for middle school students (ages 12-15) and adult self-learners, available on iOS and Android. This policy explains what data we process, how, and your rights.
The essentials: Kalc works offline. Your progress data is stored on your device and synced through your iCloud account (iOS) or Google backup (Android). We don't run a server. The only information shared with third parties is anonymous usage statistics (Firebase) and purchase management (Apple, Google, RevenueCat).
Kalc is published by LMT Digital Creations. For any privacy-related question, write to info@kalc-app.com.
Kalc is partly aimed at middle school students. If you are under 16 (under 13 in the US under COPPA), use of the app must be authorized by your parents or legal guardian. We deliberately limit data collection to the absolute minimum to comply with GDPR (Article 8) and COPPA.
The following information is stored only on your device and synced via iCloud (iOS) or Google backup (Android):
On iOS, this sync runs through your personal Apple account (iCloud). On Android, it runs through Google backup (Auto Backup). In both cases, we have no access to this data.
When you make a purchase in the app on iOS, Apple processes the transaction. Apple also provides the iCloud infrastructure that syncs your data across your Apple devices. See Apple's privacy policy.
On Android, Google Play processes your purchases and Google backup syncs your data across your Android devices. See Google's privacy policy.
RevenueCat helps us validate your purchases against the Apple and Google servers. No personal data is shared, only an anonymous identifier and the nature of the transaction. RevenueCat does not process your first name, country, or progress data. See RevenueCat's privacy policy.
We use Firebase Analytics (Google) to understand how the app is used, for example at which step users abandon the onboarding, or which skills are practiced the most. The statistics are anonymized and aggregated. No first name, no email address, no Apple identifier is sent.
The only information sent is: your country, your school level, your premium status (free / annual / lifetime), and usage events (session started, paywall shown, etc.). See Firebase's privacy policy.
If you accept reminders, they are scheduled locally on your device via the iOS or Android system. No notification data leaves your phone. You can disable reminders at any time from Kalc Settings or from system Settings.
Under GDPR, CCPA, and other applicable privacy laws, you may at any time:
Your data remains stored on your device and in your iCloud as long as you use the app. Anonymous Firebase statistics are retained according to Google's default retention settings (14 months).
We may update this policy to reflect changes in the app or legal obligations. The date of the last update appears at the top of this document. Significant changes will be announced in the app.
For any question, erasure request, or complaint, contact us: info@kalc-app.com
You also have the right to file a complaint with your local data protection authority (in the EU, your national authority; in the US, your state attorney general; in the UK, the ICO).