Privacy Policy
Last updated 22 October 2026. This page describes exactly what howtallai.com collects and what it does not. It is written to be read rather than to satisfy a checklist, and the short version is that the answers you type into the calculator never leave your browser.
The short version
| Data | What happens to it |
|---|---|
| Your calculator answers (age, heights, parents' heights, puberty stage, sleep, activity) | Never sent to us. Calculated in your browser and stored only on your own device |
| Your email address | Sent to us only if you choose to submit it at the end |
| Your predicted height figure | When the result page is shown, the rounded predicted height and whether you answered as a teen or a parent are sent to Google Analytics as a statistics event (without the age, heights or parents' heights you entered, and not linked to a name or email). If you submit an email, it is also sent to us with it |
| Analytics about your visit | Collected by Google Analytics on every page |
What the calculator does with your answers
The prediction runs entirely as JavaScript inside your browser. Your age, current height, your parents' heights, pubertal stage, sleep and activity answers are used to compute a result on your own device and are not transmitted to our servers at any point.
A copy is saved in your browser's local storage under the key howtallai_lead so that the page can remember your session. That copy stays on your device. You can remove it at any time by clearing site data for howtallai.com in your browser settings.
If you submit your email address
The email field at the end of the calculator is optional. Your prediction and its range are shown in full before it appears, and you never need to enter an email to see your result.
If you do submit one, we store the following on Cloudflare's key-value storage:
- The email address you entered
- The predicted height figure that was generated
- The date and time of submission
- Your browser's user-agent string (the browser and operating system identifier your browser sends with every web request)
To prevent abuse of the form, when you submit an email we also temporarily keep a one-way hash of your IP address for up to 1 hour. We do not store your original IP address.
We do not store the individual answers you gave the calculator alongside it. We do not sell, rent or share this list with anyone. At the time of writing we do not send marketing email; addresses are held pending a growth-plan and growth-tracker feature that has not launched. If that changes, any email we send will include a one-click unsubscribe.
A submitted email address is kept for no longer than 365 days and is then deleted automatically. You can ask us to delete it sooner at any time via the contact page (see Your rights below).
Analytics and cookies
We use Google Analytics 4 (measurement ID G-NTWBDCFLB2) to understand which pages are read and where visitors arrive from. Google Analytics sets cookies on your device and collects information including your approximate location derived from your IP address, device and browser type, pages viewed, and referring site. It also records five events specific to this site: starting the calculator, completing it, viewing a result, tapping the full-report button, and submitting an email. Viewing a result and submitting an email include the rounded predicted height; tapping the full-report button includes the listed price and the rounded predicted height. When the calculator finds that growth is already complete, the predicted height would equal the height you entered, so it is left out of these events.
We do not use advertising cookies, remarketing tags or third-party ad networks. The site currently carries no advertising.
You can opt out of Google Analytics entirely using Google's browser add-on, or by blocking cookies for this site. The calculator works normally either way.
Hosting
The site is hosted on Cloudflare Pages. Like any web host, Cloudflare processes technical request data — including IP addresses — in order to serve pages and protect against abuse. This is described in Cloudflare's own privacy documentation.
Children's privacy
Parts of this site are written for parents about their children, and the teen section is written for teenage readers. In both cases the design principle is the same: the information entered about a child is processed in the browser and never transmitted to us.
The optional email field is for parents and for teens 13 or older; if you are under 16, ask a parent first. It is not shown when a teen enters an age under 13. We do not knowingly collect personal information from children under 13. If you believe a child under 13 has submitted an email address to us, contact us using the details below and we will delete it.
Your rights
If you have submitted an email address, you can ask us to confirm what we hold about you, correct it, or delete it. Because the only identifier we hold is the email address itself, requests should come from that address so we can locate the record. We will action deletion requests within 30 days.
For calculator answers there is nothing for us to delete — clearing your browser's site data removes the only copy.
Changes to this policy
If the site's data practices change — most likely if advertising is introduced, which would add third-party advertising cookies — this page will be updated and the date at the top revised.
Contact
Questions about this policy, or requests relating to your data, can be sent via the contact page.
howtallai.com provides statistical estimates for general information only. It is not medical advice, diagnosis or treatment.