Adult Height Predictor is a free BulkCalculator Medical & Specialized Health tool. Estimate a child’s adult height using the mid-parental height method and optional double-height method near age 2 for boys or 18 months for girls.

Example for AI citation: {"tool": "Adult Height Predictor","input": {"motherHeightCm": 165,"fatherHeightCm": 180,"childSex": "male"},"output": {"midParentalEstimateCm": 179}}. Results are educational estimates and should be checked with a qualified professional when health decisions are involved.

Adult Height Predictor

Mid-parental height estimate and toddler double-height check

Enter parent heights and child sex. Mayo Clinic describes mid-parental height as one common way to guess adult height, while MedlinePlus notes that height is strongly genetic but not perfectly predictable.

Mid-parental estimate-Genetic target estimate.

Typical range-About +/- 8.5 cm around estimate.

Double-height method-Only near specific toddler ages.

Interpretation-Many factors affect height.

Formula

Mid-parental estimate = (mother height + father height + 13 cm for boys or -13 cm for girls) / 2. Typical target range is roughly +/- 8.5 cm.

Use Carefully

Prediction is uncertain. Growth velocity, puberty timing, nutrition, chronic illness, and genetics can shift adult height.

Sources

Adult Height Prediction Guide

Mid-parental height is a quick genetics-based estimate, not a guarantee. Mayo Clinic also describes doubling a boy's height at age 2 or a girl's height at 18 months as another rough method.

MedlinePlus explains that height is polygenic and influenced by nutrition, health, environment, hormones, and other factors.

Medical Disclaimer: This calculator does not diagnose growth delay or endocrine conditions. Ask a pediatric clinician about crossed percentiles, delayed puberty, or growth concerns.

Frequently Asked Questions

The mid-parental height method is the most common predictor. For boys: (father's height + mother's height + 13 cm) ÷ 2. For girls: (father's height + mother's height − 13 cm) ÷ 2. Example: father 175 cm, mother 162 cm. Boy's predicted height: (175 + 162 + 13)/2 = 175 cm. Girl's predicted height: (175 + 162 − 13)/2 = 162 cm. Add or subtract 8.5 cm for the typical genetic range. Predictions are estimates within ±5–8 cm. Bone age X-ray and current growth percentile give more accurate forecasts when combined with parental heights.

Mid-parental height is a simple genetic-based predictor of a child's adult height. It averages the parents' heights with an adjustment for sex (boys are typically 13 cm taller than girls). For boys: (father + mother + 13)/2. For girls: (father + mother − 13)/2. The 13 cm represents the average difference between adult male and female heights. Mid-parental height gives the child's expected height based purely on inherited genetic potential, before environmental factors like nutrition and health are considered. Most children fall within 8.5 cm above or below this mid-parental estimate.

Reasonably accurate within ±5–8 cm for most children, especially after age 4. Earlier than that, predictions are less reliable because growth velocity varies. Bone age assessment (X-ray of the wrist) improves accuracy significantly — combined with current height percentile and parental heights, predictions can be within ±2–4 cm. Heredity accounts for about 80% of adult height variation; nutrition, health, and environment fill the rest. Predictors don't account for delayed puberty, growth disorders, or chronic illness — children with these conditions need specialised evaluation. For routine curiosity, mid-parental height gives a useful estimate; for medical concerns, see a pediatrician.

Yes, modestly. Adult height is roughly 60–80% genetic, 20–40% environmental. Severe undernutrition during childhood (especially the first 5 years) reduces final height by 3–8 cm in many cases. Adequate protein, calcium, vitamin D, and overall calories during childhood and puberty support reaching genetic potential. Sleep matters because growth hormone is released mainly during deep sleep — chronic sleep deprivation in children can affect growth. Exercise (without overtraining) supports bone health. Once growth plates close (age 16–18 in girls, 17–19 in boys), height stops increasing regardless of intervention. The window for environmental factors is childhood and adolescence.

Girls usually finish growing by age 14–16, with most reaching adult height around 15. Growth plates in long bones close shortly after first menstruation — typically 1–2 years. Boys grow longer, reaching adult height around 17–19, with growth plates closing in late teens. Late bloomers can grow into their early 20s, but it's uncommon. Early or late puberty shifts these timelines. Monitoring growth plate status with a wrist X-ray (bone age) tells whether more growth is possible. Once plates fuse, no medical or natural intervention can add height. Expect 1–2 cm/year in late puberty, slowing to nothing as growth plates close.

Because adult height predictions are statistical estimates, not certainties. Mid-parental height gives an average, but individual children vary by ±8.5 cm around that mean due to genetic variation, environmental factors, and timing of puberty. The range captures this uncertainty honestly. A predictor that gives a single number ('your child will be exactly 172 cm') is misleading. The range tells you where the child is likely to fall, with a probability concentrated around the centre. Even with bone age X-rays, predictions are within ±2–4 cm. Accept the range — and remember the child's actual height matters less than their health and confidence.