📏 Child Height Predictor
By ToolNimba Health Team · Reviewed by ToolNimba Editorial Review, health content review · Updated 2026-06-19
This is a rough estimate based on parental heights only, not medical advice. The mid-parental method has a wide margin of about plus or minus 8.5 cm (3.3 inches), and a child's real adult height also depends on nutrition, overall health, genetics beyond the parents, and timing of puberty. If you have concerns about your child's growth, speak to a paediatrician or use proper growth charts.
This child height predictor estimates how tall your child is likely to be as an adult using the mid-parental height method, the simple formula doctors often use as a quick check. Just choose the child's sex and enter the mother's and father's heights, in centimetres or feet and inches, and you will see the predicted adult height along with a realistic range. It works the same for a baby, a toddler, or an older child, because the estimate is based on the parents, not the child's current height.
What is the Child Height Predictor?
The mid-parental method estimates a child's adult height from the average of the two parents' heights, adjusted for the child's sex. The idea is that height is strongly inherited, so a child tends to land near the genetic midpoint of their parents. On average boys end up taller than girls, so the formula adds about 13 cm (roughly 5 inches) for a boy and subtracts the same amount for a girl. This is sometimes called the target height or genetic height.
The single number the formula gives is only the centre of a likely range, not a guarantee. Real adult heights for children with the same parents scatter around that midpoint, so the accepted prediction interval is about plus or minus 8.5 cm (about 3.3 inches). That means a predicted height of 176 cm really points to a likely range of roughly 168 cm to 185 cm. Most children finish within that band, but some land outside it.
The method is deliberately simple and ignores many real factors. Nutrition, general health, chronic illness, hormones, and how early or late puberty arrives all influence final height. Two children with identical parents can differ by several centimetres. The mid-parental estimate is best treated as a friendly ballpark figure, useful for curiosity and for spotting when a child is growing very differently from the family pattern, rather than a precise forecast.
When to use it
- Satisfying a parent's curiosity about how tall a baby or toddler might grow up to be.
- Getting a quick genetic target height to compare against a child's current growth-chart percentile.
- Helping a teenager understand their likely adult height range during a growth spurt.
- Estimating sizing needs over time, for example when planning long-term clothing or sports involvement.
How to use the Child Height Predictor
- Choose whether the child is a boy or a girl.
- Pick metric (cm) or imperial (feet and inches) units.
- Enter the mother's height.
- Enter the father's height.
- Read the predicted adult height and the likely range that appears instantly.
Formula & method
Worked examples
A boy whose mother is 162 cm and father is 178 cm tall.
- Add the parents: 178 + 162 = 340 cm
- Add 13 cm for a boy: 340 + 13 = 353 cm
- Divide by 2: 353 / 2 = 176.5 cm
- Apply the range: 176.5 minus 8.5 = 168.0 cm, 176.5 + 8.5 = 185.0 cm
Result: Predicted adult height about 176.5 cm, likely range 168.0 to 185.0 cm.
A girl whose mother is 162 cm and father is 178 cm tall.
- Add the parents: 178 + 162 = 340 cm
- Subtract 13 cm for a girl: 340 minus 13 = 327 cm
- Divide by 2: 327 / 2 = 163.5 cm
- Apply the range: 163.5 minus 8.5 = 155.0 cm, 163.5 + 8.5 = 172.0 cm
Result: Predicted adult height about 163.5 cm, likely range 155.0 to 172.0 cm.
Predicted adult height by parents (mid-parental method, midpoint values)
| Mother | Father | Boy prediction | Girl prediction |
|---|---|---|---|
| 155 cm | 170 cm | 169.0 cm | 156.0 cm |
| 160 cm | 175 cm | 174.0 cm | 161.0 cm |
| 165 cm | 180 cm | 179.0 cm | 166.0 cm |
| 170 cm | 185 cm | 184.0 cm | 171.0 cm |
| 175 cm | 190 cm | 189.0 cm | 176.0 cm |
Quick height conversion reference
| Centimetres | Feet and inches |
|---|---|
| 155 cm | 5 ft 1 in |
| 165 cm | 5 ft 5 in |
| 175 cm | 5 ft 9 in |
| 185 cm | 6 ft 1 in |
| 195 cm | 6 ft 5 in |
Common mistakes to avoid
- Treating the number as exact. The prediction is the centre of a wide range, about plus or minus 8.5 cm. A child can comfortably finish several centimetres above or below the figure, so read it as a ballpark, not a promise.
- Swapping the boy and girl adjustment. You add 13 cm for a boy and subtract 13 cm for a girl. Mixing these up shifts the estimate by 13 cm in the wrong direction, so always select the correct sex first.
- Mixing up units. Entering one parent in centimetres and the other in inches gives a nonsense result. Pick metric or imperial and enter both parents the same way.
- Ignoring health and puberty timing. The formula uses parents only. Nutrition, chronic illness, hormones, and early or late puberty can move a child well outside the predicted range, so it is no substitute for a growth check by a doctor.
Glossary
- Mid-parental height
- The estimate of a child's adult height based on the average of the two parents' heights, adjusted for sex. Also called target or genetic height.
- Target height
- Another name for the mid-parental estimate, the height a child is genetically aimed at reaching as an adult.
- Prediction interval
- The range around the estimate within which most children actually finish, here about plus or minus 8.5 cm.
- Growth chart
- A medical chart that plots a child's height and weight against age-based percentiles to track growth over time.
- Percentile
- A ranking that shows how a child compares with peers, for example the 50th percentile is the median height for that age.
Frequently asked questions
How accurate is the mid-parental height method?
It is a useful rough guide, not a precise forecast. The accepted prediction interval is about plus or minus 8.5 cm (around 3.3 inches), so most children finish within that band around the estimate, but individual results vary with nutrition, health, and puberty timing.
How tall will my child be?
Enter the child's sex and both parents' heights and the tool gives a predicted adult height plus a likely range. For a boy it averages the parents and adds 13 cm; for a girl it averages them and subtracts 13 cm. Treat the result as an estimate centred in a wide range.
Why does the formula add or subtract 13 cm?
On average adult men are about 13 cm (roughly 5 inches) taller than adult women. The adjustment shifts the parental average up for a boy and down for a girl to reflect that typical difference between the sexes.
Can a child grow taller than both parents?
Yes. Because the real range spans about plus or minus 8.5 cm around the estimate, and because nutrition and health have improved across generations, some children end up taller than both parents. The reverse can also happen.
Does this work for a baby or toddler?
Yes. The mid-parental method is based only on the parents, not the child's current size, so it works at any age. For younger children a doctor may instead track growth-chart percentiles, which use the child's own measurements over time.
What else affects how tall a child becomes?
Beyond the parents, final height depends on nutrition, general and chronic health, hormones, sleep, physical activity, and especially the timing of puberty. Genetics from earlier generations also plays a role, which is why predictions are only approximate.
Sources
- Predicting a child's adult height , Nemours KidsHealth
- Assessment of growth: mid-parental height and target range , U.S. National Library of Medicine (PubMed)