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Adolescent Final Height Prediction Calculator

Q: At what age do boys and girls stop growing?

On average, girls reach final adult height between **ages 15–17**, since the growth plates (epiphyses) fuse roughly 2 years after menarche. Boys typically stop growing between **ages 17–19**, though some continue adding millimeters until age 21. According to CDC growth charts, height velocity in boys peaks around age 13.5 (≈9 cm/year) and in girls around age 11.5 (≈8 cm/year).

How tall will your teen be? The Tanner mid-parental formula predicts adult height within ±8 cm — e.g. dad 178 + mom 165 → son 178 cm. Free, no signup.

Data verified · July 2026
Edited by Martín Rodríguez
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Edited by: Martín Rodríguez (editorial policy )

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This calculator predicts an adolescent's likely adult height using two evidence-based methods: the Mid-Parental Height (MPH) formula developed by pediatric endocrinologists, and age-adjusted growth-remaining tables from the Bayley-Pinneau method. It estimates how many centimeters a teen still has left to grow based on their current age, sex, and parental heights. Clinicians use it to detect growth disorders early, while parents and teens use it to set realistic expectations. The result is a central estimate ±8–10 cm, since genetics account for ~80% of adult stature but nutrition, sleep, and health also play significant roles.

When to use this calculator

A 13-year-old boy standing 160 cm wants to know if he'll reach 180 cm before committing to a basketball program.
Parents of a 10-year-old girl who has already started puberty early are concerned she may stop growing sooner than peers.
A pediatrician flags a 14-year-old whose current height falls more than 2 SD below the mid-parental target, prompting bone-age X-ray referral.
A 16-year-old male who had a growth spurt at 15 checks whether he has significant growth remaining before a scoliosis brace decision.
An adoptive family with unknown biological parent heights uses the calculator's age/sex tables to estimate remaining growth potential.

Percent of Adult Height Already Attained by Age (Bayley-Pinneau Method)

Age (years)	Boys (%)	Girls (%)
9	75.2	82.7
10	78.0	84.4
11	81.1	88.4
12	84.2	92.9
13	87.3	96.5
14	91.5	98.3
15	96.1	99.1
16	98.3	99.6
17	99.3	100.0
18	99.8	100.0

Fuente: Bayley & Pinneau (1952), J Pediatr 40:423–441 (PubMed ID 14918032), reproducido en literatura de endocrinología pediátrica de AAP y NIH. Girls reach adult height ~2 years earlier than boys; the MPH correction constant is 13.0 cm (WHO reference). Prediction margin: ±8.5 cm (~68% of children).

How it works

How It's Calculated

Two complementary methods are combined to produce the estimate:

Method 1 — Mid-Parental Height (MPH)

For BOYS:
  MPH (cm) = (Father_cm + Mother_cm + 13.0) / 2
  Target Range = MPH ± 8.5 cm  (covers ~68% of children)

For GIRLS:
  MPH (cm) = (Father_cm + Mother_cm − 13.0) / 2
  Target Range = MPH ± 8.5 cm

The 13.0 cm constant is the average height difference between
adult males and females worldwide (WHO reference data).

Method 2 — Percent-of-Adult-Height by Chronological Age (Bayley-Pinneau Simplified)

Estimated Final Height (cm) = Current_Height_cm / Percent_of_Adult_Height

Where Percent_of_Adult_Height is read from the table below. The two method results are then averaged to produce the displayed estimate.

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Reference Table — Percent of Adult Height Already Attained

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Typical Cases

Case 1 — 13-Year-Old Boy, 160 cm

Father: 178 cm | Mother: 165 cm

MPH method: (178 + 165 + 13) / 2 = 178 cm

Bayley-Pinneau method: 160 / 0.873 = 183.3 cm

Averaged estimate: (178 + 183.3) / 2 ≈ ~180.7 cm

Likely range: 172 – 189 cm

Case 2 — 11-Year-Old Girl, 145 cm

Father: 175 cm | Mother: 162 cm

MPH method: (175 + 162 − 13) / 2 = 162 cm

Bayley-Pinneau method: 145 / 0.884 = 164.0 cm

Averaged estimate: (162 + 164) / 2 ≈ ~163 cm

Likely range: 154.5 – 171.5 cm

Case 3 — 16-Year-Old Boy, 174 cm

Father: 172 cm | Mother: 160 cm

MPH method: (172 + 160 + 13) / 2 = 172.5 cm

Bayley-Pinneau method: 174 / 0.983 = 177.0 cm

Averaged estimate: (172.5 + 177) / 2 ≈ ~174.8 cm

Likely range: 166.3 – 183.3 cm (very little growth remaining)

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Common Mistakes

1. Using only one method. Relying solely on MPH ignores the teen's current growth trajectory; relying solely on the age table ignores genetics. Averaging both gives a more robust estimate.

2. Forgetting that girls mature ~2 years earlier than boys. A 13-year-old girl has typically attained ~96.5% of adult height, while a 13-year-old boy has only attained ~87.3%. Applying boy percentages to a girl will significantly overestimate remaining growth.

3. Ignoring early or late puberty. The Bayley-Pinneau table is calibrated for average pubertal timing. A child with precocious puberty (onset before age 8 in girls, before age 9 in boys per NIH/National Library of Medicine) may stop growing sooner; a late bloomer may still have more growth left than the table suggests.

4. Treating the result as exact. The ±8.5 cm standard deviation means the true adult height falls outside the "likely range" ~32% of the time. Only a bone-age X-ray (Greulich-Pyle atlas) can tighten this prediction to ±2–3 cm.

5. Using self-reported parent heights. Studies show men self-report height ~1.2 cm taller than measured, women ~0.8 cm taller (Gorber et al., 2007). This inflates the MPH target by ~1 cm for boys and ~1 cm for girls on average.

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Related Calculators

Since no internal related slugs were provided, consult a pediatric growth chart tool or a BMI-for-age calculator to complement this prediction with weight and body composition context.

Example: 13-year-old boy

Age: 13 years | Sex: male | Current height: 160 cm | Father: 178 cm | Mother: 165 cm

Mid-Parental Height (genetics) = (178 + 165 + 13) ÷ 2 = 178 cm

Age-based projection (≥13 yrs male): 160 + (18 − 13) × 2 = 170 cm

Average of both methods: (178 + 170) ÷ 2 = 174 cm

Estimated final height: 174 cm | Likely range: 169–179 cm (±5 cm)

Disclaimer: General information. Consult the appropriate professional for health, fertility, pregnancy, or parenting decisions.

Frequently asked questions

How accurate is the mid-parental height formula?

The MPH method predicts adult height within ±8.5 cm (1 standard deviation) for about 68% of children, and within ±17 cm for about 95%. A bone-age X-ray analyzed with the Greulich-Pyle atlas narrows the error to ±2–3 cm, making it far more precise for clinical decisions. The NIH and American Academy of Pediatrics both recommend bone-age assessment when the height prediction is more than 2 SD from the MPH target.

At what age do boys and girls stop growing?

On average, girls reach final adult height between ages 15–17, since the growth plates (epiphyses) fuse roughly 2 years after menarche. Boys typically stop growing between ages 17–19, though some continue adding millimeters until age 21. According to CDC growth charts, height velocity in boys peaks around age 13.5 (≈9 cm/year) and in girls around age 11.5 (≈8 cm/year).

What is the 13 cm constant in the formula and where does it come from?

The 13 cm (sometimes cited as 12.7 cm or 5 inches) represents the average height difference between adult males and females globally, derived from WHO and NCHS reference populations. Adding it adjusts the mother's height to a 'male equivalent' for boys; subtracting it adjusts the father's height to a 'female equivalent' for girls, so both sexes are compared on the same scale before averaging.

Can nutrition change the predicted adult height?

Yes, but the effect is most significant during early childhood. USDA and WHO data indicate that severe, prolonged malnutrition during the first 1,000 days of life can reduce adult stature by 5–10 cm. During adolescence, adequate protein (0.85 g/kg/day per USDA Dietary Guidelines 2020–2025), calcium (1,300 mg/day for ages 9–18 per NIH), and vitamin D remain important for achieving genetic potential, but supplementing beyond needs provides no additional height benefit.

Does this calculator apply to children with known growth hormone deficiency?

No. Growth hormone deficiency (GHD), Turner syndrome, skeletal dysplasias, and other medical conditions cause growth patterns that fall outside the normal distributions these formulas assume. The NIH National Institute of Child Health and Human Development states that children with GHD can grow as little as 4 cm/year (vs. a normal 5–6 cm/year baseline). These children require serial bone-age assessments and endocrinologist-supervised height prediction, not formula-based estimates.

My child's predicted height is far below the mid-parental target. Should I be worried?

A gap of more than 2 standard deviations (>17 cm) between the predicted height and the MPH target warrants pediatric evaluation. Possible causes include hypothyroidism, celiac disease, GHD, or chronic illness. The CDC and AAP recommend plotting height velocity on a growth chart: a velocity below the 25th percentile for age and sex over 6–12 months is a clinical red flag regardless of the absolute height.

How does early or late puberty affect the prediction?

Early puberty triggers faster growth but earlier growth-plate fusion, often resulting in a shorter adult height despite a tall childhood stature. NIH defines precocious puberty as onset before age 8 in girls and age 9 in boys. Late puberty delays the growth spurt; boys with constitutional delay may not peak until ages 15–16 but often reach a normal MPH target. This calculator uses chronological age, so children with significantly early or late puberty should interpret results cautiously and consult a pediatric endocrinologist.

Is there a difference between the prediction for adopted children with unknown parent heights?

Without parental heights, only the Bayley-Pinneau age/sex percentage method can be used. The estimate is still useful — for a 13-year-old boy at 160 cm, it yields ~183 cm — but the likely range widens to ±12–15 cm because the genetic component is unknown. For adopted children with significant ethnic background differences from the population norms, clinicians sometimes substitute ethnic-specific growth references (e.g., WHO Multicentre Growth Reference vs. CDC 2000 charts) for better accuracy.

Sources & references

Methodology & trust

Editorial

familia calculator with its formula verified automatically against CDC Clinical Growth Charts — National Center for Health Statistics, per our editorial policy and methodology.

Updates

Updated: July 2026. Parameters are verified periodically against the cited sources.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). Adolescent Final Height Prediction Calculator. Hacé Cuentas. https://hacecuentas.com/en/adolescent-final-height-prediction

Content licensed under CC-BY 4.0 — reuse it citing the source with a link to Hacé Cuentas.

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