Privacy Policy

Last Updated: 10 September 2026

Our Privacy Commitment

Tallwise predicts adult height from growth science. Most of its users are teenagers or parents logging a child. That is exactly why everything you enter stays on your phone. There is no account, no server of ours, no tracking and no advertising.

Information Stored Locally on Your Device

Stored only on your device (SwiftData and UserDefaults) and not transmitted to us:

• Profile: biological sex, date of birth, height, weight, parents' heights, puberty-stage answers, sleep, activity and diet answers
• Logs: height entries and daily habit entries you add
• Settings: language, units, subscription status

Predictions are calculated on the device from public growth references (CDC 2000 growth charts, the Khamis-Roche method). No health data is sent anywhere to make a prediction.

Purchases (In-App Purchase)

Tallwise offers an optional Tallwise Plus subscription through Apple's In-App Purchase system. To manage subscriptions we use RevenueCat:

• The payment is handled entirely by Apple. We never see your card or billing details.
• RevenueCat receives a randomly generated app user ID, your purchase/receipt information and basic device/app data in order to validate the purchase. It never receives your profile or logs.
• We use this information only to grant and restore your Plus access.

RevenueCat's privacy information: https://www.revenuecat.com/privacy

Data We Do Not Collect

• No accounts, no email, no passwords, no third-party login.
• No advertising or ad identifiers (IDFA). We display no ads and never ask for tracking permission.
• No third-party analytics, tracking or profiling SDKs.
• No camera, microphone, photos, contacts or location access.
• No health data ever reaches us.

Children and Teenagers

Tallwise is designed to be used by teenagers and by parents on behalf of children. Because the app collects nothing, there is nothing for us to hold about a child. If you are a parent and want a child's data removed, delete it in More → Delete all my data or delete the app.

Sharing

If you use Share my prediction, the app creates an image on your device and hands it to the iOS share sheet. Where it goes is your choice.

Your Rights

As a Sweden/EU-based developer we follow the General Data Protection Regulation (GDPR) for everyone who uses the app. Because your data is on your device, you exercise most rights yourself: view and edit everything in the app, and erase it with Delete all my data. Purchase records held by our processor can be deleted on request; contact us at avelan.sverige@gmail.com.

Changes

If a future version adds any feature that sends data off the device (for example optional iCloud sync through your own account), this page will say so before it ships.