Privacy notice · effective 20 August 2026
Your height information stays on your device.
This notice explains how the Centile iPhone app and this website handle information. The app is local-first; the website has no account, analytics, cookies or tracking.
Information used on your device
The app may use information entered by a teenager or parent/guardian:
- teen or parent route;
- birth month and year;
- the published female or male calculation reference;
- current height and, for the personal estimate, current weight;
- two biological-parent adult heights;
- dated height measurements;
- height and weight display preferences;
- routine and habit completion for up to 90 days; and
- an optional local monthly-reminder setting and time.
The app does not ask for a name, account, email address, phone number, postal address, exact birth date, location, photo, contacts, medical history, diagnosis, medication or free-text health journal.
Why the app uses it
The information is used on the device to calculate and explain educational height estimates, display measurement history, restore preferences, show optional routine history and schedule an optional local reminder.
Routine or habit completion never changes a height prediction.
What the operator receives
Under the current release design, the app does not transmit profile, measurement, prediction, routine or reminder information to SLT Workshop Ltd. It has no app account, cloud database, analytics, advertising, tracking, product AI or third-party SDK.
Apple separately operates the App Store, StoreKit purchases and device-backup services. SLT Workshop Ltd does not receive payment-card details from the app.
The app and website are different
The iPhone app makes no network request in normal use. Serving this website necessarily sends a request to the selected hosting provider, which processes standard request information such as an IP address and browser type to deliver and protect the pages. SLT Workshop Ltd adds no analytics, advertising, cookies or tracking to the site.
The family-range calculator runs entirely in the browser. The heights entered into it are not transmitted to SLT Workshop Ltd and are not retained after the page is closed.
Storage, device access and backups
The app stores one protected local record in its private area on the device. Someone who can unlock the device and open the app may be able to see the information.
Apple device backups may copy app data according to the device owner’s Apple and backup settings. The app does not control or delete an existing copy retained in an Apple backup.
Retention
Routine and habit-completion records are retained for at most the current local day plus the preceding 89 calendar days. Other local fields remain until the user deletes local data, removes the app or erases the device, subject to Apple’s backup behaviour.
Deletion and correction
Users can correct entries in the app and choose Delete local data from Profile. The app removes its live local record, clears local state and cancels its reminder.
Because the operator does not receive the on-device record, support cannot view, export, correct or delete it remotely.
Teen and parent routes
The product is intended for people aged 13 or older and for parents or guardians using it for or with a teenager. It is not offered through Apple’s Kids Category.
Changes and contact
Material changes to data handling must be reflected in this notice and the App Store privacy answers. Accounts, analytics, uploads, cloud sync, advertising, remote AI, support attachments or third-party SDKs require a new privacy assessment.
Privacy, security and support questions can be sent to support@centile.app. The effective date shown above will be updated if this notice changes materially.