Adult Height Calculator
Created by: Olivia Harper
Last updated:
A child's expected adult height can be estimated two ways: from the parents' heights (their average plus 2.5 inches for a boy, minus 2.5 inches for a girl), and from where the child sits on the CDC growth chart today. This calculator does both and averages them. Enter the age, current height and, if you know them, both parents' heights.
Adult Height Calculator
HealthPredict adult height from current height, age and the parents’ heights, using CDC growth charts.
Parents' heights are optional but improve the estimate.
Average height by age (CDC growth charts)
The 50th percentile (median) height for U.S. children from the CDC 2000 growth charts. Half of children are taller than this at each age and half are shorter.
| Age | Boys | Girls |
|---|---|---|
| 2 | 2′10″ (87 cm) | 2′10″ (85 cm) |
| 3 | 3′2″ (95 cm) | 3′1″ (94 cm) |
| 4 | 3′4″ (103 cm) | 3′4″ (101 cm) |
| 5 | 3′7″ (109 cm) | 3′7″ (108 cm) |
| 6 | 3′10″ (116 cm) | 3′9″ (115 cm) |
| 7 | 4′0″ (122 cm) | 4′0″ (122 cm) |
| 8 | 4′2″ (128 cm) | 4′2″ (128 cm) |
| 9 | 4′5″ (134 cm) | 4′4″ (133 cm) |
| 10 | 4′7″ (139 cm) | 4′6″ (138 cm) |
| 11 | 4′9″ (144 cm) | 4′9″ (144 cm) |
| 12 | 4′11″ (149 cm) | 5′0″ (151 cm) |
| 13 | 5′2″ (156 cm) | 5′2″ (157 cm) |
| 14 | 5′5″ (164 cm) | 5′3″ (160 cm) |
| 15 | 5′7″ (170 cm) | 5′4″ (162 cm) |
| 16 | 5′8″ (174 cm) | 5′4″ (163 cm) |
| 17 | 5′9″ (175 cm) | 5′4″ (163 cm) |
| 18 | 5′9″ (176 cm) | 5′4″ (163 cm) |
| Adult (20) | 5′10″ (177 cm) | 5′4″ (163 cm) |
How the adult height prediction works
1. Mid-parental (genetic target) height
Boys: (father's height + mother's height + 13 cm) ÷ 2. Girls: (father's height + mother's height − 13 cm) ÷ 2. In inches, add or subtract 5 inches instead of 13 cm. The 13 cm reflects the average difference in adult height between men and women. Most children end up within about 8.5 cm (3.3 in) of this target.
2. Percentile tracking
The calculator finds where the child's current height sits on the CDC stature-for-age chart, for example the 70th percentile for a 9-year-old girl, and reads off the adult height at the same percentile. Children tend to stay near the same percentile through childhood, but many move during puberty because they start it earlier or later than average.
3. Combined estimate
When you enter both parents' heights, the prediction is the average of the two methods. That uses the family's genetics and the child's actual growth so far.
Worked example
A 10-year-old boy is 4′8″ (142 cm). His father is 5′10″ (178 cm) and his mother is 5′4″ (163 cm).
- Mid-parental target: (178 + 163 + 13) ÷ 2 = 177 cm, or 5′10″.
- Percentile: 142 cm is about the 70th percentile for a 10-year-old boy, which projects to about 180 cm (5′11″) as an adult.
- Prediction: the average, about 179 cm (5′10″), with a likely range of roughly 173 to 184 cm.
Frequently Asked Questions
How do you calculate expected adult height?
Two common methods are used. The mid-parental method averages the parents’ heights and adds 6.5 cm (2.5 in) for a boy or subtracts 6.5 cm for a girl. The percentile method finds the child’s height percentile on the CDC growth chart and assumes they stay on it until adulthood. This calculator shows both and averages them when you enter the parents’ heights.
How accurate is an adult height calculator?
Treat the result as a range, not a single number. About 95% of children end up within roughly 8.5 cm (3.3 in) of their mid-parental target. The percentile method is least reliable around puberty, because early developers look tall for their age and late developers look short. A doctor can narrow the estimate with a bone age X-ray.
How tall will I be if my dad is 6 feet and my mom is 5 foot 5?
The parents average 68.5 inches. A boy’s mid-parental target is 68.5 + 2.5 = 71 inches (5′11″), and a girl’s is 68.5 − 2.5 = 66 inches (5′6″), each give or take about 3.3 inches.
At what age do you stop growing?
Most girls reach their adult height by about 15 to 16, around two years after their first period. Most boys finish growing by about 17 to 18, though some grow a little into their early twenties. The CDC median barely changes after those ages.
Can I predict my height if I am already an adult?
Once the growth plates close, usually by the late teens, height no longer increases. If you are 18 or older, the calculator treats your current height as your adult height and shows your percentile against the CDC age-20 reference.
Can nutrition or sleep increase my height?
Good nutrition and enough sleep help a child reach their genetic potential, and long-term malnutrition or untreated illness can stunt growth. They do not add height beyond that potential, and nothing increases height once the growth plates have closed.
When should I talk to a doctor about my child’s height?
Ask a pediatrician if your child is below the 3rd or above the 97th percentile, drops across two major percentile lines on the growth chart, grows less than about 5 cm (2 in) a year between age 3 and puberty, or is far from the family pattern.
Sources and References
- CDC: Stature-for-age LMS parameters, 2 to 20 years. Used for the percentiles, the projection and the table above.
- Tanner JM, Goldstein H, Whitehouse RH. Standards for children's height at ages 2–9 years allowing for height of parents. Arch Dis Child. 1970;45(244):755–762. The origin of the mid-parental target height.
This calculator gives an estimate for general information. It is not a diagnosis.