Height projection
Mid-parental prediction blended with CDC-style growth-curve carry-forward, shown with the accuracy it has actually earned. Log more, and the range tightens.
Coming to iOS & Android
You can't change your genes.
You can change whether you reach them.
Tall-O projects your adult height from your own growth data — then coaches the sleep, nutrition and training that decide how much of that potential you actually reach.
- Your projection in about two minutes — before you make an account
- Accuracy that climbs every time you log a real measurement
- Posture photos stay on your device, always
How it works
Three steps, and the first one is free.
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1
Tell us where you're starting
Sex, age, your height, your parents' heights, and a short fitness assessment. It takes about two minutes and doesn't need an account.
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2
Get your range, free
The mid-parental method blended with growth-curve carry-forward gives you a projected adult height — with an honest accuracy figure attached, not a number pretending to be certain.
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3
Then do something about it
Daily sport, nutrition and sleep targets built around the projection. Every measurement you log narrows the range and sharpens the guidance.
What's inside
A prediction is the hook. The habits are the product.
The Grow board
Sport, nutrition and sleep as one daily engine — exercise timers, a water counter, meal logging with macro bars and deficiency alerts, and a sleep logger with a wind-down routine.
Insights
Your real height against the projection, weekly habit bars, the correlations between them, milestones — and a private posture photo log that never leaves your phone.
Andy, your coach
An AI coach with read-only tools over your own data. Ask why your sleep score slipped and it goes and looks, rather than guessing from a summary.
Community
A feed of people doing exactly the same thing. Ask the awkward questions somewhere they're normal questions.
Streaks that survive real life
Weekly targets rather than all-or-nothing chains, so one bad night doesn't cost you a month of momentum.
Andy
Most app chatbots get a paragraph. Andy gets tools.
The usual approach pastes a summary of your data into a prompt and hopes. Andy is an agent: it decides what it needs and goes and reads it — your profile and projection, your height history, habit streaks, nutrition, sleep, achievements.
It keeps a memory of your goals, obstacles and commitments between conversations, but deliberately never caches your numbers. Those are read live every time, so it can't confidently quote you a stat from last month.
Your account is fixed server-side before Andy ever runs, so there is no question you can ask — and no instruction anyone can plant — that makes it read someone else's data.
Andy
your coach
Why did my sleep score drop this week?
You averaged 6h 12m, down from 7h 40m. Four of the drops were Thursday to
Sunday, and all four were late starts rather than early wake-ups.
Growth hormone peaks in the first deep-sleep block, so bedtime drift costs
you more than the hour it looks like. Want to move your wind-down 30
minutes earlier for the weekend?
Privacy
Health data is the easiest thing to be careless with.
Posture photos never leave your phone
They're written to your device's own storage. There is no upload path.
Attribution is kept separate
We measure which ad brought you here so we can stop paying for the ones that don't work. It is never joined to your height or health data.
Accounts merge only on a verified email
Signing in with Google or Apple links to your existing account only when the provider asserts the address is verified — never on an unverified one.
FAQ
The questions worth asking first.
Will this make me taller?
No — and be suspicious of anything that claims it will. Adult height is mostly genetic. What isn't fixed is how close you get to your own ceiling: sleep, nutrition and training during your growing years all move that, sometimes by a lot. Tall-O works on the part you control and is honest about the part you don't.
How accurate is the projection?
It starts as a genetics-based range from your and your parents' heights, and it tells you its accuracy rather than hiding it. As you log real measurements over time, growth-curve carry-forward takes over from pure genetics and the range narrows.
Who is it for?
People who are still growing — broadly teens and early twenties — and parents tracking a child's growth. If you've finished growing, the projection has nothing left to predict, though the habit and sleep tools still stand on their own.
What's free and what's paid?
Onboarding and your genetics-based range are free, before you create an account. Pro unlocks your precise projection, the full projection chart and unlimited height updates.
When does it launch?
We're finishing the last round of testing now. Join the list above and you'll get one email the day it's live — that's the only thing the list is used for.