Centile privacy

Information used on your device

The app may use information entered by a teenager or parent/guardian:

teen or parent route;
an optional first name or nickname for the person whose growth is being tracked;
birth month and year;
the published female or male calculation reference;
current height and, for ages 13 to 17½, current weight, which only the personal estimate uses;
the adult heights of two biological parents;
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 require a name and does not ask for an 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. If entered, the optional first name or nickname is used only to label the Home, report and Progress screens.

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 Limited. It has no app account, cloud database, advertising, ad tracking, product AI.

Anonymous counts. To learn which parts of Centile people use, the app and this site send simple counts, such as “a result was shown” or “the Plus page was opened”. Each count carries only the app version, the type of phone, the store’s country, the day and, on some new installs, which version of the Plus page the phone shows. No name, account, device ID, advertising ID or height data is sent, no IP address is kept, and nothing is shared with anyone else. A count can’t be traced back to you.

Purchase records. From Centile 1.1.5, when someone buys or renews Centile Plus, the app tells RevenueCat, a service that keeps purchase records for SLT Workshop Limited. RevenueCat receives the purchase as Apple or Google Play reports it (the plan, the price, the store’s country and the transaction details) and a random ID the app makes on the phone. RevenueCat may also receive which version of the Plus page the phone shows. Like any app request, it also carries the type of phone, its system version and language, and on iPhone the identifier Apple gives each app maker for that phone. RevenueCat receives no name, email, height or other profile details and no advertising ID. It processes these records on SLT Workshop Limited’s behalf so we can see how many people subscribe. It does not decide whether Plus is on: Apple and Google Play still handle the payment and the subscription.

The app bundles Lottie, an open-source animation library, to display animation files included in the app. Centile does not use Lottie to download remote animations or send measurements or other profile data. Its bundled privacy manifest declares no tracking, and one kind of collected data: product interaction, for analytics, not linked to the person. This is separate from the purchase services Apple and Google Play run, and from Apple’s device services.

Apple separately operates the App Store, StoreKit purchases, App Store review prompts and device-backup services. On Android, Google separately operates Google Play and Google Play Billing purchases. SLT Workshop Limited does not receive payment-card details from the app.

The app and website are different

The app does not send profile, measurement, prediction, routine or reminder information to SLT Workshop Limited. On iPhone it uses Apple's App Store services to load subscription offers and check verified purchase access. On Android it uses Google Play Billing to do the same. On both, each purchase is also recorded with RevenueCat, as described above. Serving this website necessarily sends a request to the selected hosting provider. What that host keeps is set out below. SLT Workshop Limited adds no advertising, cookies or ad tracking to the site. The site’s only counts are the anonymous counts above: a visit to the store-link page and a tap on a store button.

The adult height calculator runs entirely in the browser. The heights entered into it are not transmitted to SLT Workshop Limited and are not retained after the page is closed.

The website host

Cloudflare Pages hosts this site. To deliver each page it keeps standard request logs: the IP address the request came from, the page asked for, the time, and the browser type. SLT Workshop Limited does not use those logs to identify visitors. The site sets no cookies, and the anonymous counts described above hold no personal data.

When you email support

An email to support@centile.app arrives with your email address, the time you sent it and whatever you wrote. We keep it only as long as we need to answer you, then delete it. Ask, and we delete it sooner. Please don’t send health details, heights or attachments.

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.

On iPhone, 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.

On Android, the app excludes its data from Google backup and from device transfer, so there is no backup copy.

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 on iPhone to Apple’s backup behaviour.

Deletion and correction

Users can edit the details the range is worked out from, with confirmed recalculation, and edit or delete individual height checks. Deleting a height check changes your latest height and your progress line. Your Plus range comes from the latest check with both height and weight. Delete that check and the range is worked out again from the one before. The Plus range card shows the date it comes from. Users can also choose Delete local data from Profile; the app removes its complete 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.

To have a purchase record deleted from RevenueCat, email support@centile.app with the order number from the store’s receipt. Apple and Google Play keep their own records of the payment.

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, the App Store privacy answers and Google Play’s data safety section. Accounts, analytics beyond the anonymous counts, uploads, cloud sync, advertising, remote AI, support attachments or further 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.