Percentage of Predicted Adult Height Achieved Calculator
How This Differs From Our Other Height Calculators
This is a progress tool, not a prediction tool — and that's the key difference from two calculators already on HGB. Our Child Height Prediction Calculator answers "how tall will my child likely be as an adult?" by generating a new estimate from current measurements and parental heights. This calculator skips that step entirely: you supply a predicted adult height you already have, and it answers a completely different question — "how much of that height has my child already reached?"
It's also distinct from our Peak Height Velocity Calculator, which estimates puberty timing from physical signs like breast development, menarche, or voice changes. This calculator uses only height measurements — no signs checklist — and expresses progress as a single percentage rather than a growth-spurt phase.
What "Percentage of Adult Height" Actually Means
Percentage of adult height (sometimes written %AH or %PAH in research) is a simple but useful maturity indicator: it expresses a child's current height as a share of the height they're expected to reach as an adult. A 10-year-old girl who is 138 cm tall with a predicted adult height of 163 cm has reached about 85% of that prediction — a single number that captures both how tall she is now and how much growing she likely has left.
Researchers have used this percentage as a practical, non-invasive stand-in for skeletal maturity assessment, since it correlates well with bone age without requiring an X-ray.3 It's also widely used in youth sports science to group young athletes by biological maturity rather than by chronological age alone, since two 13-year-olds can be at very different points in their growth even with the same birthday.
Maturity Bands: Pre-, Circa-, and Post-Growth-Spurt
Sports science research has settled on a simple three-band way to classify where a young athlete sits in their growth spurt, based on percentage of predicted adult height reached.4 This calculator uses the same bands as a general reference point:
| Band | % of Predicted Adult Height | What It Generally Means |
|---|---|---|
| Pre-PHV | ≤ 87% | Growth spurt likely hasn't peaked yet |
| Circa-PHV | 88–95% | Likely at or near the fastest point of the growth spurt |
| Post-PHV | > 95% | Fastest growth is likely behind them |
PHV stands for peak height velocity — the single fastest-growing point of puberty. These bands were developed and validated primarily in youth athletes, so treat them here as a general orientation rather than a precise individual timeline.
Typical % of Adult Height Reached by Age
To judge whether your child's percentage is running ahead of, in line with, or behind typical pace, this calculator compares it against average population data by age and sex.1,2
| Age | Typical % (Girls) | Typical % (Boys) |
|---|---|---|
| 4 | ~62% | ~58% |
| 6 | ~70% | ~66% |
| 8 | ~78% | ~73% |
| 10 | ~84% | ~78% |
| 12 | ~92% | ~84% |
| 14 | ~98% | ~93% |
| 16 | ~99.7% | ~98% |
Approximate values derived from median height-for-age data in the 2000 CDC growth charts.2 Girls typically reach a given percentage earlier than boys, reflecting their earlier average pubertal timing.
Where to Get a Predicted Adult Height
Frequently Asked Questions
What if I don't have a predicted adult height yet?
Use our Child Height Prediction Calculator first to generate one, then come back here to track progress against it over time.
My child's percentage is well above the typical range for their age. Is that a problem?
Not necessarily. It often just means they're maturing earlier than average, which is common and usually normal. If it's paired with signs of very early puberty (before age 8 in girls or age 9 in boys), it's worth mentioning to a pediatrician.
Can this percentage change a lot over a few months?
A little movement is normal, especially heading into or through a growth spurt. A large, sudden jump or drop is more likely to reflect a measurement inconsistency or a change in the predicted height itself than a real shift in maturity.
Is this the same as a bone age result?
No, but it's related. Percentage of adult height is used in research as a practical stand-in for skeletal maturity because the two are closely correlated, but an actual bone age reading from an X-ray remains more precise for clinical decisions.
Why do the maturity bands (pre/circa/post-PHV) matter?
They're mainly used in youth sports settings to group children of similar biological maturity rather than similar age, since maturity differences can meaningfully affect size, strength, and performance at the same chronological age. For a general family audience, they're simply a useful, research-backed way to interpret what a given percentage typically means.
