Every parent wonders: how tall will my child be? While you cannot predict height with 100% certainty, science gives us highly accurate formulas based on parents’ height and the child’s current measurements. This guide explains every method, includes a full child height prediction table, and answers the most common questions about child growth.
Boy’s height = (Father’s height + Mother’s height + 5 inches) ÷ 2
Girl’s height = (Father’s height + Mother’s height − 5 inches) ÷ 2
How to Predict a Child’s Height — 3 Methods
Method 1: Mid-Parental Height Formula (Most Common)
This is the most widely used method by pediatricians. It estimates a child’s adult height based solely on the parents’ heights:
For Boys: (Father's height + Mother's height + 5 in) / 2 For Girls: (Father's height + Mother's height - 5 in) / 2 Example (Boy): Father = 5'10" (70 in), Mother = 5'5" (65 in) Predicted height = (70 + 65 + 5) / 2 = 140 / 2 = 70 inches = 5'10"
In centimetres:
For Boys: (Father's cm + Mother's cm + 13 cm) / 2 For Girls: (Father's cm + Mother's cm - 13 cm) / 2
Method 2: Double the Height at Age 2
A simple rule: a child’s height at age 2 is approximately half their adult height.
Predicted Adult Height = Height at Age 2 x 2 Example: Child is 34 inches at age 2 Predicted height = 34 x 2 = 68 inches = 5'8"
Note: For girls, use height at age 18 months x 2. Boys at 24 months.
Method 3: Bone Age X-ray (Most Accurate)
Doctors can take an X-ray of a child’s left hand and wrist to assess bone age (skeletal maturity). This is more accurate than any formula but requires a medical consultation.
Child Height Predictor Table — Based on Parents’ Height
Predicted adult height for boys (in feet & inches):
| Mother ↓ Father → | 5′6″ | 5′8″ | 5′10″ | 6′0″ | 6′2″ |
|---|---|---|---|---|---|
| 5′0″ | 5′5.5″ | 5′6.5″ | 5′7.5″ | 5′8.5″ | 5′9.5″ |
| 5′2″ | 5′6.5″ | 5′7.5″ | 5′8.5″ | 5′9.5″ | 5′10.5″ |
| 5′4″ | 5′7.5″ | 5′8.5″ | 5′9.5″ | 5′10.5″ | 5′11.5″ |
| 5′6″ | 5′8.5″ | 5′9.5″ | 5′10.5″ | 5′11.5″ | 6′0.5″ |
Predicted adult height for girls (in feet & inches):
| Mother ↓ Father → | 5′6″ | 5′8″ | 5′10″ | 6′0″ | 6′2″ |
|---|---|---|---|---|---|
| 5′0″ | 5′0.5″ | 5′1.5″ | 5′2.5″ | 5′3.5″ | 5′4.5″ |
| 5′2″ | 5′1.5″ | 5′2.5″ | 5′3.5″ | 5′4.5″ | 5′5.5″ |
| 5′4″ | 5′2.5″ | 5′3.5″ | 5′4.5″ | 5′5.5″ | 5′6.5″ |
| 5′6″ | 5′3.5″ | 5′4.5″ | 5′5.5″ | 5′6.5″ | 5′7.5″ |
Average Child Height by Age (Boys & Girls)
| Age | Boys Height (avg) | Girls Height (avg) |
|---|---|---|
| 1 year | 29–30 in (74–76 cm) | 28.5–29.5 in (72–75 cm) |
| 2 years | 33–35 in (84–89 cm) | 32–34 in (81–86 cm) |
| 4 years | 39–41 in (99–104 cm) | 38–40 in (97–102 cm) |
| 6 years | 44–46 in (112–117 cm) | 43–45 in (109–114 cm) |
| 8 years | 49–51 in (124–130 cm) | 48–50 in (122–127 cm) |
| 10 years | 53–56 in (135–142 cm) | 53–56 in (135–142 cm) |
| 12 years | 57–62 in (145–157 cm) | 58–63 in (147–160 cm) |
| 14 years | 62–66 in (157–168 cm) | 61–64 in (155–163 cm) |
| 16 years | 66–69 in (168–175 cm) | 62–65 in (158–165 cm) |
| 18 years (adult) | 68–70 in (173–178 cm) | 63–65 in (160–165 cm) |
What Factors Affect a Child’s Height?
| Factor | Impact on Height |
|---|---|
| Genetics (Parents’ Height) | 60–80% of adult height |
| Nutrition | 10–20% impact (protein, calcium, Vitamin D) |
| Sleep Quality | Growth hormone released during deep sleep |
| Physical Activity | Exercise stimulates growth hormone production |
| Health Conditions | Chronic illness can stunt growth |
| Hormones | Growth hormone deficiency reduces height |
When Do Children Stop Growing?
- Girls: Stop growing 2–3 years after their first period — usually by age 14–16
- Boys: Continue growing until age 17–18, sometimes up to 21
- Growth plates (epiphyseal plates) close when puberty ends, stopping height increase
How to Help Your Child Reach Their Maximum Height Potential
- Protein-rich diet — eggs, milk, chicken, lentils support muscle and bone growth
- Calcium and Vitamin D — essential for strong, long bones (dairy, sunlight, leafy greens)
- Adequate sleep — children need 9–11 hours; growth hormone peaks during deep sleep
- Regular exercise — swimming, basketball, and stretching all support growth
- Avoid smoking — studies show secondhand smoke exposure reduces child height
Frequently Asked Questions
How tall will my child be based on parents’ height?
Use the Mid-Parental Height formula: Boys = (Dad’s height + Mom’s height + 5 inches) ÷ 2. Girls = (Dad’s height + Mom’s height − 5 inches) ÷ 2. This prediction is accurate within ±2–4 inches for 95% of children.
Is a child’s height at 2 years half their adult height?
Yes, this is a reliable rule of thumb. A boy’s height at age 2 doubled predicts adult height. For girls, use age 18 months. However, the Mid-Parental Height formula is slightly more accurate.
Can nutrition increase a child’s height beyond their genetic potential?
No. Good nutrition helps a child reach their genetic maximum height, but cannot exceed it. Malnutrition, however, can significantly reduce final height below genetic potential.
At what age is a child half their adult height?
Boys reach half their adult height at approximately 24–25 months. Girls reach half their adult height slightly earlier, at around 18–20 months.
How accurate are height prediction formulas?
The Mid-Parental Height formula is accurate within ±4 inches (10 cm) for about 95% of children. The Khamis-Roche method (using child’s current height, weight, age, and parents’ heights) is considered the most accurate non-medical formula, accurate within 1.7 inches for girls and 2.1 inches for boys.
Conclusion
Predicting your child’s height is easy with the Mid-Parental Height formula: add both parents’ heights, adjust by ±5 inches for gender, then divide by 2. While genetics determines 60–80% of height, proper nutrition, sleep, and exercise help every child reach their full potential. Use our free height and health calculators for instant predictions and growth tracking.