Height Calculator – Predict Adult Height
Child
Units
Height converter – cm ↔ feet & inches
Enter both parents' heights and tap
Predict Height.
Height Calculator – How Tall Will My Child Be?
This free height calculator predicts how tall a child is likely to be as an adult, using the parents' heights and the mid-parental height method – the same "target height" formula paediatricians use when they check a child's growth chart. Enter the father's and mother's height in centimetres or in feet and inches, choose boy or girl, and you get the predicted adult height in both units with the likely range. A built-in height converter also turns centimetres into feet and inches and back.
How to Use the Height Calculator
- Select boy or girl. The formula adjusts for the average height difference between men and women.
- Choose centimetres or feet and inches.
- Enter the biological father's and mother's heights, measured without shoes if possible.
- Tap "Predict Height" to see the predicted adult height and the likely range.
- Need a quick conversion? Open the height converter below the button.
The Mid-Parental Height Formula
Adult height is strongly inherited. The mid-parental (target) height averages the parents' heights after adjusting for the roughly 13 cm (about 5 inches) difference between average adult men and women:
Boy: (Father's height + Mother's height + 13 cm) ÷ 2
Girl: (Father's height + Mother's height − 13 cm) ÷ 2
In inches, use 5 instead of 13 cm. About 95% of children end up within ±8.5 cm (about 3.3 inches) of this target, which is why the calculator shows a range as well as a single number.
Example
A father who is 178 cm (5 ft 10 in) and a mother who is 163 cm (5 ft 4 in):
- Son: (178 + 163 + 13) ÷ 2 = 177 cm (5 ft 9.7 in), likely between 168.5 and 185.5 cm.
- Daughter: (178 + 163 − 13) ÷ 2 = 164 cm (5 ft 4.6 in), likely between 155.5 and 172.5 cm.
What Else Affects a Child's Height?
- Nutrition: enough protein, calcium, vitamin D, zinc and total energy during childhood and adolescence.
- Sleep and activity: growth hormone is released mainly during deep sleep; regular physical activity supports healthy growth.
- Health conditions: chronic illness, coeliac disease, thyroid problems or growth hormone deficiency can reduce growth.
- Puberty timing: early or late puberty changes when the growth spurt happens, and sometimes the final height.
- Generational trends: children in many countries grow a little taller than their parents because of better nutrition and health care.
When Do Children Stop Growing?
Children grow fastest in the first year of life, then about 5–6 cm a year through childhood. During puberty there is a growth spurt – usually between about 10 and 14 years in girls and 12 and 16 years in boys. Most girls reach their adult height by around 15–16 years and most boys by around 17–18 years, once the growth plates in the long bones close.
Other Ways to Predict Height
Doubling height at age 2: a rough rule of thumb is that a boy's height at 2 years or a girl's height at 18 months is about half of their adult height. Growth charts: a child who stays on the same percentile line tends to reach a similar percentile as an adult. Bone age: doctors can estimate remaining growth from a hand X-ray, which is the most accurate method but needs a specialist. The mid-parental method is the simplest and is widely used as a first check.
Height Conversion Table
| Centimetres | Feet and inches |
|---|---|
| 152.4 cm | 5 ft 0 in |
| 160 cm | 5 ft 3 in |
| 165 cm | 5 ft 5 in |
| 170 cm | 5 ft 6.9 in |
| 175 cm | 5 ft 8.9 in |
| 177.8 cm | 5 ft 10 in |
| 182.9 cm | 6 ft 0 in |
1 inch = 2.54 cm and 1 foot = 12 inches = 30.48 cm.
When to See a Doctor
Speak to a paediatrician or GP if your child's height is well below the predicted range for the family, if growth seems to slow down or stop, if the child drops across two or more percentile lines on the growth chart, or if puberty starts very early or has not started by around 13 in girls or 14 in boys.
Frequently Asked Questions
How accurate is the height calculator?
The mid-parental method predicts the most likely adult height, and about 95% of children end up within ±8.5 cm of it. It does not account for nutrition, illness or puberty timing.
How do I calculate my child's height from the parents' heights?
For a boy add 13 cm to the sum of both parents' heights and divide by 2. For a girl subtract 13 cm and divide by 2.
Can a child be taller than both parents?
Yes. The prediction is an average; many children are taller than both parents, especially when nutrition and health are better than in the parents' generation.
At what age do girls and boys stop growing?
Most girls stop growing around 15–16 years and most boys around 17–18 years, although some continue to grow slightly into their early twenties.
How many cm is 5 feet 7 inches?
5 ft 7 in = 67 inches × 2.54 = 170.2 cm.
Is my data saved?
No. The calculation runs in your browser and nothing is stored.
Sources: Tanner JM et al., mid-parental (target) height method; standard paediatric growth assessment guidance.