Tallmark: for parents and guardians
Version 1.0
Effective date: 10 October 2026
Last updated 10 October 2026
In short
Tallmark is a height journal and habit game for teenagers aged 13 to 19, with a cartoon giraffe called Tally.
Everything your teenager enters in their journal (height, weight, meals, sleep and so on) stays on their phone. The app has no ads, no analytics and no tracking.
It has one optional social space, Community, where teens post short notes about habits under a made-up nickname and an animal. There are no private messages, no photos and no links, it is filtered and moderated, and nothing from your teenager's records is ever sent to it.
It has one optional AI chat, Chat with Tally, on the Coach tab. It is off until your teenager turns it on on a screen that says exactly what is sent, and asks under-18s to check with you first. Once on, each question goes with a summary of their records (age, recent heights and weight, the estimate, last week's logs — never their name, birthday, your heights, puberty answers or any note) to an AI model, Anthropic's Claude, run for us by kie.ai or by Anthropic itself. Anthropic keeps it for up to about 30 days; kie.ai does not say how long it keeps requests. Safety questions are answered on the phone and never sent.
It has one more optional feature, photo analysis of a meal. It is also off until your teenager turns it on, on a screen that says what is sent: a meal photo (with its location data removed) or the words they type into Describe it, with a portion value (currently always "all of it"), never any record. It goes through the same server to the same AI model and is kept for the same time. They can log a meal by typing it in with nothing leaving the phone.
It shows a predicted adult height with a likely range — an estimate that is not clinically calibrated. It never promises growth, and it says plainly that no habit adds height.
There is no BMI, no weight goal, no diet score, and no calorie display unless it is turned on.
You can look through the records together (Export my records), and delete everything in one step (Reset all my data), which also removes your teenager from Community.
Tallmark is made by New Version Ltd, a small New Zealand company. If you have a question this page does not answer, email tallmark.support@newversion.studio.
1. What the app is for
Lots of teenagers wonder how tall they will be, and the internet is full of "grow taller" products that do not work. Tallmark gives them an honest place to:
record their height, dated, and see it on a chart;
see an approximate range for their adult height, worked out from published methods, with the uncertainty shown;
keep a light journal of movement, meals, sleep, water, mood and (if they want) weight;
learn what the evidence actually says, from short tips and a Coach with reviewed answers — and, if they turn it on, an AI chat (section 10);
build everyday habits through a daily quest, streaks, XP and badges that reward taking part, never a change in their body.
2. What it asks, and why
Setting up takes about five minutes: 24 short screens, two of which are information only. All answers stay on the phone. None of them is ever sent to Community.
Date of birth: Growth references are by age. Under-13s are stopped here
Sex assigned at birth: Growth charts exist for two bodies, with different timing. The app asks which chart fits, not about gender identity
Current height, and optional weight: The starting measurement. One estimate method uses weight; weight is optional
Parents' heights: Family height is the strongest clue to adult height. "Not sure" is an accepted answer
Tall relatives, shoe size: Kept because they were given. Shoe size does not change the estimate
Five puberty questions (growth spurt, body hair, skin, voice or breast development, facial hair or periods): How much growing is left depends much more on puberty stage than on age. These follow a self-report questionnaire used in research (the Pubertal Development Scale). If periods have started, the app asks at what age
Growth in the last year, usual sleep, activity, sports, eating, goals: Shapes tips and quests
A height they have in mind: Optional. Kept, and never scored or compared
Daily reminder: Off unless they turn it on
The app may offer to ask the puberty questions again after about four months, because answers go out of date. That is an offer, not a requirement, and "Not now" is always an option.
3. What it deliberately does not do
No BMI, no "healthy weight" range, no weight goal, and no opinion about weight going up or down. Weight is recorded only because one estimate method uses it.
No diet scores. Meals are described, never graded, and no food is called good, bad, junk or a treat.
No calorie display by default. Calories are hidden unless turned on in Settings, and there is never a calorie target.
No mood scores. Moods are never averaged, streaked or compared.
No comparing heights with other users. The only comparison is the growth-chart percentile, which is a population reference. In Community, no height, weight or age is ever shown, and the guidelines ask members not to compare them.
No private messages, no photos and no links, anywhere in the app. The only social space is Community (section 5A), which is optional. The AI chat (section 10) is a conversation with the app, not with other people.
No ads, no analytics, no tracking. There is one optional purchase, Tallmark Plus (extra guided routines), through your Apple ID or Google account — the estimate, trackers and safety pages are free. A 7-day free trial may be offered, with a reminder two days before it ends; to cancel, use your Apple ID or Google Play subscription settings. We ask teenagers to check with a parent or guardian before buying.
No collection of their records. We never keep anything your teenager enters in their journal. What we receive is what they choose to post in Community (section 5A) and, if they turn on the AI chat, the questions and record summary that pass through our server to be answered and are not kept by us (section 10).
No celebration of a measurement. A height log is acknowledged, never cheered, because the most common honest result of measuring is no change.
No countdowns to a measurement or to the end of growing.
No "grow taller" promises. The app says clearly that no exercise, food, supplement, sleep or posture habit adds centimetres.
4. The estimate, honestly
The Predicted adult height on the main screen is one number, for example 177 cm, shown with a likely range on the Growth tracker (likely 172–183 cm). It is an estimate and uncalibrated: we have not tested how often real adult heights fall inside the range, so we do not claim an accuracy, and adult height may be outside it. It is not a diagnosis.
The line "Taller than N% of teens your age" compares one measurement with the US CDC 2000 growth charts. It is a population comparison, not a grade. Every percentile is a normal height for somebody.
Full details: Health disclaimer (https://sites.google.com/view/tallmark/medical-disclaimer) and Health information sources (https://sites.google.com/view/tallmark/health-source).
5. Looking at the records together
Their records are not sent to you or to us, so the only way to see them is on the phone, with your teenager, or through an export they make. The export does not include Community posts.
Settings › Your data › Export my records creates a .zip file containing records.json and one spreadsheet (CSV) per tracker. The phone's share menu opens, and they choose where it goes, such as to Files or to you by message. The export is not encrypted, so keep it private.
An export is also the only way to keep the records when changing phones. Tallmark's records are deliberately kept out of iCloud and Google Drive backups and out of Android phone-to-phone transfer. There is no import yet.
Please respect that this is your teenager's journal. It works best as something you look at together, when they want to.
5A. Community
Community is a tab in the app where teenagers can post short text notes about everyday habits, reply and react. It is optional: nothing is sent until your teenager taps Join Community and agrees to the Community guidelines (https://sites.google.com/view/tallmark/community-guidelines).
What it is and is not
Posts are short (a title of up to 80 characters, an optional body of up to 600), in one of seven topics: Questions, Habit wins, Move, Food, Sleep, Water and Chat. Replies are up to 300 characters.
Reactions are positive only: Cheer, Helpful, Same. There are no downvotes.
There are no private messages, no photos and no links. An automatic filter rejects phone numbers, email addresses, @handles and "add me on Snapchat / Instagram / Discord…".
Your teenager appears as a generated nickname (for example "Sleepy Fox 42") and an animal picture. No real name, no email, no password, no photo. The server uses an anonymous account with no email attached.
No height, weight or age is ever shown or sent. None of their records can be read by Community.
Posting earns nothing: no XP, no streak, no reward.
Any member can see any public post. The app asks for a date of birth at setup and refuses anyone under 13, but does not verify age beyond that.
Safety
Every post and reply is checked by an automatic filter. Posts that mention supplements, hormones, surgery, claims about growing a number of centimetres or self-harm are held: only the author sees them until a person has reviewed them.
Anyone can report a post (it is hidden for them straight away). When three different members report the same thing, it is hidden for everyone until a person has reviewed it.
Anyone can block another member.
Being reported never penalises anyone by itself. A person at New Version Ltd decides whether something breaks the guidelines; removals count as strikes, and repeated removals can pause that member's access. There are daily limits on posts and replies.
A person at New Version Ltd reviews reported and held items. We aim to do so within 24 hours.
If your teenager types words that suggest they may be in danger into the post box, the app shows a link to the helplines.
Where the posts are kept
Posts are stored on servers in the United States, and are deleted automatically after 90 days (removed items 30 days after removal). Your teenager can delete their own posts and replies at any time.
Leaving
Settings › Community › Leave Community and delete my posts removes their nickname, posts, replies, reactions and anonymous account from the server. Their journal is not affected.
Settings › Reset all my data does the same and also deletes the journal. If the phone is offline, the app asks whether to try later or reset anyway. If they reset anyway, their posts stay on the server for up to 90 days.
A parent or guardian can ask us to remove their teenager's Community content by emailing tallmark.support@newversion.studio. Please include their nickname if you know it, but not their measurements or health details.
If you do not want your teenager to use Community, the simplest step is to talk about it with them: it is a choice inside the app, behind a welcome sheet, and they can leave at any time.
6. Deleting everything
One entry: open it in its tracker and choose Delete.
Everything: Settings › Reset all my data deletes every record, estimate, streak, badge, reminder and setting, the Coach conversation, turns the AI chat off, and returns the app to its welcome screen. It cannot be undone.
The app: deleting Tallmark from the phone deletes its records too. It does not remove Community posts: use Leave Community and delete my posts first, or email us.
We hold no copy of the journal, so we cannot delete it for you and we cannot recover anything that has been deleted. Community content is the exception: we do hold it, and can remove it (section 5A).
7. Notifications
If your teenager turns on the daily reminder, the phone shows one reminder a day at the time they chose, plus an optional evening nudge at 8:30 pm that can be turned off separately. They are scheduled on the phone, not sent over the internet, and the wording is general, such as "Quest time". They never show a measurement, a weight or a mood. You can also manage them in the phone's notification settings.
8. When a doctor is worth a visit
Most differences in height and timing are normal. It is worth seeing a doctor if your teenager:
has not grown at all in six months or more while you would still expect growth, or is growing much more slowly than they were before (dropping to a lower line on a growth chart);
is much shorter or taller than you would expect from the family's heights;
has no breast development by 13, or no period by 15 or about three years after breasts began to develop (girls), or no growth of the testicles by 14 (boys). Late starts are common and often run in families (it can help to remember when you went through puberty), so a check is usually reassuring;
is losing weight without trying, is often very tired, or often unwell;
is worried about eating, weight or how their body looks;
often seems low, anxious, withdrawn or not themselves.
A doctor can measure accurately, track growth over time and arrange tests that no app can.
9. Talking about height and body image
Height can matter a lot to teenagers. A few things that tend to help:
Talk about height as information, not a verdict. Every height is a normal height for someone.
Avoid comparisons with siblings, friends or classmates. People grow at different times, and starting later is not being behind.
Be sceptical together of "grow taller" products, pills, insoles and stretching programmes. The honest answer is that nothing adds height after growth plates close, and before then, the basics (enough food, sleep and activity) protect the growing that is already coming.
Keep food neutral. Talk about eating enough and eating a variety, not about good and bad food or about weight.
Watch for worry that is growing. Measuring many times a day, avoiding food, over-exercising, or being very upset by a number are signs to talk gently and, if needed, see a doctor.
If your teenager is struggling, If you need help now (https://sites.google.com/view/tallmark/safety-resources) lists helplines by country, including eating-disorder support for families.
10. The Coach and Tally
The Coach's quick questions are a fixed set of reviewed answers (sleep, food, posture, supplements, exercise and the estimate) on the phone. Nothing is sent.
Chat with Tally (optional, on the Coach tab) lets your teenager type their own questions, and an AI model writes the answers: Anthropic's Claude, reached through our own server and then kie.ai or Anthropic.
It is off until they turn it on. The screen that does it lists what is sent, what never goes and who handles it, and says "Under 18? Check with a parent or guardian before you turn this on." The app cannot check that they did, so this is a good thing to look at together.
What goes with each question: their age in years and sex, up to six recent heights and the latest weight, the app's estimate exactly as the app shows it, today's quest and streak, which routines they can play, and the last 7 days of meals (names and nutrients; calories only if they turned them on), water, sleep, the mood face they picked, movement and Train sessions, plus the last few chat messages. Never their name, date of birth, your heights, a dream height, their puberty answers (including periods), any note they wrote (including mood notes), photos or anything from Community.
Who keeps what: our server keeps no messages (only a daily message count under a random id). Anthropic keeps what it was sent for up to about 30 days, longer only if flagged for a safety review or required by law. kie.ai, which our server tries first, does not publish how long it keeps requests. Both process it in the United States.
What the AI is told: that it is talking to a teenager; never to promise height, make its own height prediction, discuss dieting or weight loss, or comment on their body; and to send anything worrying to a doctor or a trusted adult. Our server also checks each answer for a height that is not in the records before it is shown. AI answers can still be wrong, and they are not medical advice.
Turning it off: Settings › Chat with Tally, one tap. Reset all my data turns it off and deletes the conversation.
Limits: there is a daily limit, so a lot of chatting ends in "come back tomorrow".
Photo analysis of a meal (optional, when adding a meal) is a separate switch with its own screen. If your teenager turns it on, a photo of a meal (shrunk, location data removed) or the words they type into Describe it go, with a portion value (currently always "all of it"), their units and a random id, to our server and on to the same AI model through kie.ai or Anthropic, which sends back a guess at the foods and nutrients that they can change before saving. No records, name, birth date, height or weight go with it; the photo stays on the phone with the meal. Our server keeps no photo; the retention is the same as for the chat. A photo can show faces, a room or a document, so it is worth telling your teenager to photograph only the plate. Type it in never uses the internet. Turning it off: Settings › Meal photos. The estimates are guesses, and the app says so; meals are never scored.
Community posts are separate and are written by other teens, not the Coach.
Tally, when you tap him, can read back your teenager's own records and open the right screen to log something. What is typed in his panel is understood by simple rules on the phone, is not saved, and is gone when the app closes; that Tally is not an AI and does not claim to be. In the Coach tab's chat, Tally is an AI character, and says so if asked.
If anything mentions self-harm, suicide, feeling unsafe, an eating disorder, pain or medicine — in the quick questions, the chat or his panel — the app gives a short, reviewed safety answer on the phone, without sending anything that points to a trusted adult, a health professional or emergency services, and to local helplines. They are not a substitute for a person.
11. Legal pages
Privacy Policy (https://sites.google.com/view/tallmark/privacy-policy)
Terms of Use (https://sites.google.com/view/tallmark/terms-of-use)
Community guidelines (https://sites.google.com/view/tallmark/community-guidelines)
Health disclaimer (https://sites.google.com/view/tallmark/medical-disclaimer)
Support and FAQ (https://sites.google.com/view/tallmark/support)
12. Contact
New Version Ltd, New Zealand
tallmark.support@newversion.studio
Please do not send us your teenager's measurements or health details. We never need them to help. To ask us to remove Community content, a nickname is enough.