Height Calculator: Predict Child’s Adult Height Using Khamis-Roche Method

  • Adam
  • November 5, 2025

Calculate your child’s predicted adult height using the accurate Khamis-Roche method. Includes mid-parental height calculator, height converter, and growth charts guide.

Height Calculator

Predict Child's Adult Height Using Khamis-Roche Method & Mid-Parental Height

📏 Pro Tips for Accurate Height Predictions: Measure height without shoes on flat surface, heels against wall, head straight. Use accurate scales for weight. Record parental heights precisely. Age in years and decimal months needed (5.5 = 5 years 6 months). More accurate for children 3+ years old. Genetics accounts for 60-80% of height.

Khamis-Roche Height Prediction

Khamis-Roche Method:
This method uses regression analysis based on:
- Child's current height
- Child's current weight
- Child's age
- Mother's height
- Father's height
Accuracy: ~90% for ages 3-18

Most accurate for children 3+ years old, especially ages 4-9. Less accurate for very young or teenagers near final height.

✅ Predicted Adult Height:

Mid-Parental Height Prediction

Mid-Parental Height Method:
Boys = (Mother + Father) ÷ 2 + 2.5 inches (6.4 cm)
Girls = (Mother + Father) ÷ 2 - 2.5 inches (6.4 cm)

Simple method, uses parental heights only
Accuracy: ~75-80% (wider margin of error)

Useful for predicting height before birth or for very young children. Less accurate than Khamis-Roche but simpler to use.

✅ Predicted Adult Height:

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📊 Factors Affecting Child's Height
Genetics (60-80%):

Parental heights most important predictor. Children tend toward average of parents' heights (regression toward mean). Tall parents likely have taller children, but not always extreme heights.

Nutrition (10-20%):

Protein: builds bones and muscles. Calcium & Vitamin D: bone strength and density. Zinc: growth hormone function. Iron: oxygen transport. Iodine: thyroid function. Malnutrition can reduce final height by 5-10 cm.

Sleep (5-10%):

Growth hormone (somatotropin) released during deep sleep. Recommended sleep: ages 1-2 (11-14 hours), ages 3-5 (10-13 hours), ages 6-12 (9-12 hours), ages 13-18 (8-10 hours).

Exercise & Physical Activity:

Strengthens bones and muscles. Supports healthy weight. Improves overall health. Regular activity (60+ minutes daily) supports optimal growth.

Health & Medical Conditions:

Chronic illness: can stunt growth. Hormonal conditions: thyroid problems, GH deficiency affect height. Genetic conditions: certain syndromes affect height. Early treatment of health issues supports normal growth.

Socioeconomic Factors:

Access to nutrition, healthcare, safe living environment. Stress levels. Quality of care. Children from higher socioeconomic backgrounds average 5 cm taller in some studies.

Environmental Factors:

Climate: cold climates associated with slightly shorter stature. Altitude: living at high altitude may affect growth. Pollution exposure: air quality affects health.

👶 Growth Patterns & Growth Spurts
Infancy (0-2 years):

Fastest growth period. Babies grow about 10 inches (25 cm) in first year. Growth rate slows in second year (~5 inches/12 cm). Birth weight triples by 1 year.

Early Childhood (2-6 years):

Growth continues but slower. Children grow ~3 inches (7.5 cm) per year. Growth becomes more steady and predictable. Foundation for adult height established.

Middle Childhood (6-12 years):

Steady growth ~2-3 inches (5-7.5 cm) per year. Less variation than earlier years. Growth charts most accurate for this period. Nutrition especially important.

Puberty (10-16 years, varies by child):

Adolescent growth spurt: rapid height increase. Girls: spurt ~2 years before boys. Growth rate: 3-5+ inches per year during spurt. Lasts 2-3 years typically. Growth velocity peaks then plateaus.

Post-Puberty/Young Adult (16+ years):

Growth rate slows significantly. Girls typically stop by 16-18 years. Boys continue until 18-20+ years. Final 1-2 inches often gained after perceived "full height." Growth plates close and growth stops.

📈 How to Support Healthy Growth
Nutrition:
  • Eat balanced diet: proteins, whole grains, fruits, vegetables, dairy
  • Adequate protein: 0.5-1 gram per pound bodyweight daily
  • Calcium sources: milk, cheese, yogurt, leafy greens (1,000-1,300 mg daily)
  • Vitamin D: sunlight, fatty fish, fortified foods (600-1,000 IU daily)
  • Limit sugar, processed foods, caffeine
Sleep:
  • Maintain consistent sleep schedule (same bedtime and wake time)
  • Get recommended hours for age (8-10 hours typical for school-age)
  • Dark, cool, quiet sleep environment
  • Avoid screens 1 hour before bed
Exercise:
  • Minimum 60 minutes moderate-vigorous activity daily
  • Mix cardio, strength training, flexibility
  • Sports participation beneficial
  • Avoid excessive exercise that depletes energy for growth
Posture & Stretching:
  • Good posture can make you appear 1-2 inches taller immediately
  • Regular stretching improves flexibility and spinal alignment
  • Yoga, pilates beneficial
Health Management:
  • Regular medical checkups
  • Address health issues promptly
  • Stay current with vaccinations
  • Manage stress (high stress can inhibit growth)
❓ Frequently Asked Questions
At what age is adult height reached? +
Girls: typically 16-18 years old after puberty ends. Boys: 18-20 years or later. Growth plates close when growth stops. Rare growth possible 1-2 inches after apparent final height. Most growth complete by end of teen years.
Can you grow taller after puberty? +
Rarely. Very minimal growth (less than 1 inch) possible for 1-2 years after puberty ends. Once growth plates close, no further height growth. Posture improvements can make you appear taller without actual growth.
Is my child's height normal for age? +
Compare to CDC or WHO growth charts for your child's age and sex. 5th-95th percentile is normal range. Below 5th: discuss with pediatrician. Above 95th: also discuss. Most important: consistent growth trajectory over time.
Why is one parent's height more important? +
Both important, but roughly equal contribution from each parent. Child's height often near average of parents. However, genes don't combine predictably—child can be much taller or shorter than either parent.
Can medicine make you grow taller? +
Growth hormone therapy available for GH deficiency or specific conditions. Very expensive. Requires medical diagnosis and monitoring. Not recommended for normal short stature. Only effective during growth period.
How much can height vary from prediction? +
Khamis-Roche: typically within 2-3 inches of prediction. Mid-parental height: 4-5 inches variation possible. Factors like nutrition, health, environment cause variation. Predictions are estimates, not guarantees.
Does basketball or swimming make you taller? +
No. Sports don't increase height directly. However, good nutrition and exercise supporting sports promote healthy growth. Tall athletes may gravitate toward sports. Good overall health supports reaching genetic height potential.
What percentage is genetics vs environment? +
Genetics: 60-80% of height variation. Environment/lifestyle: 20-40%. Includes nutrition, exercise, sleep, health, socioeconomic factors. Good environment helps reach genetic potential. Poor environment may prevent it.

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