Height Calculator

About the Height Calculator

A height calculator predicts a child's likely adult height using the validated mid-parental height method, or converts height measurements between feet and inches, centimetres, and metres. Height prediction helps parents set realistic expectations, guides paediatricians tracking growth against population percentile charts, and informs planning for activities and sports where height is relevant. Our free height calculator displays your result against population height averages for several countries and shows the ±2 standard deviation range (encompassing approximately 95% of outcomes with the same genetic potential) so you understand the uncertainty in the prediction. It also converts between all common height formats: feet and inches (5'10"), decimal feet (5.833 ft), inches (70 in), centimetres (177.8 cm), and metres (1.778 m).

How It Works

Mid-parental height formula: For boys: predicted height (cm) = (father's height + mother's height + 13 cm) ÷ 2. For girls: predicted height (cm) = (father's height + mother's height − 13 cm) ÷ 2. The 13 cm offset accounts for the average height difference between adult males and females. Result has a ±10 cm (±4 inch) accuracy range reflecting genetic variation between siblings. In imperial: add 5 inches to the average of parent heights for boys; subtract 5 inches for girls. Example: father 5'10" (177.8 cm), mother 5'5" (165.1 cm). Boy prediction: (177.8+165.1+13)/2 = 177.95 cm ≈ 5'10". Girl prediction: (177.8+165.1−13)/2 = 164.95 cm ≈ 5'5". Note: bone age assessment via X-ray provides more precise predictions for individual children.

Tips & Best Practices

• ✓Accuracy context: the ±10 cm range means 68% of children with those parental heights will fall within this range. The remaining 32% will be notably taller or shorter than predicted.
• ✓Average adult heights: USA men 5'9" (175.3 cm), USA women 5'4" (162.1 cm). Netherlands men 6'0" (182.9 cm), Netherlands women 5'7" (170.7 cm) — the world's tallest country. Philippines men 5'4" (163.5 cm) — shorter average.
• ✓Growth pattern: children grow fastest in the first 2 years (approximately 25 cm in year 1, 12 cm in year 2), then steadily until the pubertal growth spurt (girls 11-13, boys 13-15).
• ✓Nutrition impact: the mid-parental formula assumes adequate nutrition and absence of growth-limiting illness. Chronic malnutrition during childhood can reduce adult height by 5-15 cm below genetic potential.
• ✓Bone age X-ray: a single X-ray of the left wrist and hand allows a radiologist to compare bone development to population norms. Children with "delayed" bone age have more growth remaining than their chronological age suggests.
• ✓Growth hormone deficiency: children growing below the 3rd percentile for their age or tracking below their genetic potential should be evaluated for growth hormone deficiency — a treatable condition.
• ✓Height and sport: the NBA average height is 6'6" (198 cm); NFL linebackers average 6'4" (193 cm). Elite volleyball players typically exceed 6'3" (190 cm) for men. Height prediction helps parents and coaches assess sport-specific potential early.
• ✓The secular trend: average heights in developed countries increased dramatically through the 20th century (approximately 10 cm per century) as nutrition and healthcare improved. This trend has slowed significantly in most wealthy nations.

Who Uses This Calculator

Parents curious about their child's predicted adult height. Paediatricians assessing whether a child's height trajectory is consistent with their genetic potential. Coaches evaluating young athletes' height potential for height-dependent sports. Adolescents anxious about their height trajectory who want reassurance. Parents planning clothing and equipment purchases for growing children. School nurses tracking growth at routine health screenings. Research paediatricians studying growth patterns and nutritional impacts.