About TallMax

TallMax is an independent, self-funded project for making growth measurements easier to understand. The complete assessment is designed for people aged 13–17; public reference charts are educational material, not an assessment for every age they cover.

Why we built it

We want someone with a height measurement to see how the result was calculated, what additional records would help, and what the result cannot establish. The core assessment is free and works without an account.

The report separates a family reference range, a current percentile, and a measured rate of change. These answer different questions. None is a diagnosis or a promise of adult height, and showing them together does not turn them into a prediction.

Editorial rules

These are constraints, not aspirations. We do not publish:

• Any predicted adult height, or any phrasing that implies one
• Any named clinical prediction method (Khamis-Roche, Tanner-Whitehouse, Bayley-Pinneau and others) without licensed parameters and independent verification
• Any claim that a behaviour adds a specific number of centimetres
• Any unvetted institutional endorsement, or any user or customer count we cannot substantiate
• Any wording that reads as diagnosis or treatment advice

The full method, including its limitations, is on the method page. It is written to be checked, not to impress.

How your data is handled

• The assessment runs entirely in your browser. Heights, dates and answers are not transmitted to a TallMax server.
• There is no account, no sign-up and no email collection in the assessment.
• Nothing is stored unless you explicitly turn on local saving, which keeps the data on your own device for 24 hours.
• There is a prominent control to clear everything at any point.
• Analytics, where present, cover page-level funnel events only. They never carry measurement values.

Medical review

TallMax provides health information for education. It does not diagnose, does not treat, and does not replace a clinician who can examine a child and read a growth history properly.

Medical review: pending. Arranging review by a qualified clinician is on the roadmap, and this page will be updated with the reviewer's name, credentials and review date once it is in place. We would rather state that plainly than imply expertise we have not secured.

When this tool is the wrong tool

If you are concerned about a child's growth, puberty, symptoms, or an existing health condition, discuss that concern with a qualified clinician. You do not need to finish this calculator or meet a numerical threshold before asking for help.

A single percentile, a stable position on a chart, or a family reference range cannot confirm that a child is healthy. The CDC describes growth charts as one contribution to an overall clinical assessment, not a sole diagnostic instrument. Our appointment preparation guide helps organise records and questions; it does not decide whether testing or treatment is needed.

Who runs this

TallMax is built and maintained by an independent developer. Corrections are welcome — if something here is wrong, we would rather hear about it than be right about it.

Editorial corrections and clinical feedback

We maintain an open channel for data corrections, clinical precision feedback, and factual inquiries:

• Email for corrections and questions: editorial@tallmax.org (or open an issue on our public repository).
• Response window: Inquiries regarding numerical calculation accuracy or referenced pediatric literature are reviewed within 5 business days.
• Correction policy: If an error in LMS interpolation, formula implementation, or clinical phrasing is verified, a dated notice will be logged in our changelog and updated immediately.

Sources

• CDC 2000 stature-for-age growth charts: https://www.cdc.gov/growthcharts/
• The method page documents every calculation this site performs.