Child Height Predictor

A child's adult height is primarily determined by genetics — specifically by the mid-parental height calculated from both parents' heights. This calculator uses the well-established Mid-Parental Height (MPH) method developed by pediatric endocrinologists, which predicts adult height within a range of ±4 inches (10 cm) for about 95% of children.

The Mid-Parental Height formula: For boys: (Father's height + Mother's height + 5 inches) ÷ 2. For girls: (Father's height + Mother's height − 5 inches) ÷ 2. The 5-inch adjustment accounts for the average height difference between men and women (approximately 5.5 inches in the US).

The 4-inch margin of error reflects the reality that while genetics determines roughly 80% of adult height, environmental factors — especially childhood nutrition — account for the remaining 20%. This is why populations that have improved their nutritional status over generations have grown taller (the secular trend in height): South Koreans born after the Korean War are on average 3–4 inches taller than those born before, reflecting improved nutrition rather than genetic change.

Factors that affect final height: Adequate protein, zinc, calcium, and vitamin D are essential for reaching genetic height potential. Chronic illness or malnutrition in childhood can stunt growth. Premature puberty (due to endocrine disruption) can initially accelerate growth but results in earlier growth plate closure and shorter final height. Adequate sleep is critical — 80–90% of growth hormone is released during deep sleep.

Growth charts (CDC and WHO) are more useful for tracking a child's individual growth trajectory than for predicting final height. A child who has consistently tracked at the 25th percentile is doing well. Concern arises when a child crosses major percentile bands upward or downward, which can indicate growth disorders warranting evaluation by a pediatric endocrinologist.