HeightVersus

Child height predictor

Estimate a child's likely adult height from both parents' heights.

This is an estimate, not medical advice. The method section below explains what it can and cannot tell you.
Child's sex

Estimated adult height

178 cm

Likely range 169.5 cm to 186.5 cm.

A population-level estimate (the mid-parental method), not a medical prediction. It knows nothing about this specific child's own growth.

See the predicted height on the board
The mid-parental method estimates a child's adult height from both parents' heights: for boys, (father's height + mother's height + 13cm) ÷ 2; for girls, (father's height + mother's height − 13cm) ÷ 2. The result is shown as a range of ±8.5cm, because genetics beyond the parents' own heights, plus environment and nutrition, mean no single number can be exact.

Worked example

  1. Parents 180 cm and 165 cm, boy
  2. Working (180 + 165 + 13) ÷ 2
  3. Result 179 cm (170.5–187.5)
A father who is 180cm and a mother who is 165cm, expecting a boy: (180 + 165 + 13) ÷ 2 = 179cm, with a likely range of 170.5–187.5cm.

Method and sources

The mid-parental height method is a long-established paediatric estimate, commonly attributed to Tanner and colleagues, and still used as a rough clinical rule of thumb alongside growth-chart tracking. It is a statistical estimate based on the parents' heights only. It has no knowledge of a specific child's actual growth, health or nutrition, and should not be treated as a diagnosis or a guarantee.

Frequently asked questions

How accurate is the mid-parental height method?

It's a population-level estimate, typically accurate to within the stated ±8.5cm range for most children, but it doesn't account for the individual child's own growth pattern, nutrition, health, or genetics beyond the parents' heights. Clinical methods (like bone-age X-rays) are more precise for an individual child.

Why is the range so wide (±8.5cm)?

Height is influenced by many genes plus environment, so even with both parents' heights known, a wide range remains genuinely likely. Reducing that range for a specific child needs their own growth data over time, not just their parents' heights.

Does this work if I don't know both parents' heights?

The formula needs both. If one parent's height is unknown, a reasonable approach is to use a country or regional average for that parent as a rough stand-in — see the average height by country calculator — but the estimate becomes less personal.

Can you grow taller after 18?

For the large majority of people, growth plates fuse by the late teens to early twenties, ending height growth. Small apparent changes after that are usually measurement variation or spinal compression through the day rather than real growth. See our full article on this for more detail.

Does this account for adopted children or step-parents?

No — the mid-parental method is a genetic estimate, so it only makes sense when applied to a child's biological parents. For other family structures, it isn't a meaningful prediction.

More tools

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