Predicting Adult Height: Estimating Based on Parent and Current Height

Adult height prediction is probabilistic, not deterministic. The Mid-Parental Height Formula provides a population-based estimate:

Mid-Parental Height Formula

• Boy: (Father's height + Mother's height + 5 in) / 2
• Girl: (Father's height + Mother's height - 5 in) / 2

Or in cm: ± 6.5 cm (boys +, girls -).

Example: 11-Year-Old Girl

• Father: 5'5" (65 in), Mother: 6'0" (72 in)
• Target height = (65 + 72 - 5) / 2 = 132 / 2 = 66 in (5'6")
• Normal range: Target ± 2 in (5'4" – 5'8") — this is the 95% prediction interval.

Other Methods

• Bone Age X-ray (left hand/wrist): Greulich-Pyle or Tanner-Whitehouse — assesses skeletal maturity; most accurate single predictor.
• Growth Charts: Track height velocity; crossing percentiles signals pathology.
• Khamis-Roche Method: Uses current height, weight, mid-parental height (no X-ray).

Key Caveats

• Genetics is polygenic; formula captures only additive component.
• Nutrition, sleep, chronic illness, medications (steroids), endocrine disorders alter trajectory.
• Puberty timing: early = shorter adult height; late = taller.

For a personalized assessment, consult a pediatric endocrinologist or adolescent medicine specialist.