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Child Height Calculator

Wondering how tall your child will be? Pop in both parents’ heights, choose boy or girl, and the Child Height Calculator estimates their adult height in centimetres and feet & inches — plus the likely range around it. It uses the classic mid-parental height formula, so think of it as a fun, genetics-based guess rather than a medical prediction of how your child will grow.

Units
Child

Estimated adult height

179 cm

about 5 ft 10 in

Likely range (±8.5 cm)

171 cm – 188 cm (5 ft 7 in – 6 ft 2 in)

Most children of these parents land somewhere in this band. It is a genetics-based estimate for fun — not a medical prediction.

How the Child Height Calculator works

This tool uses the mid-parental height method, a simple formula doctors and parents have used for years as a rough guide. You add both parents’ heights together, nudge the total up or down for the child’s sex, and halve it:

  • Boy: (mother’s cm + father’s cm + 13) ÷ 2
  • Girl: (mother’s cm + father’s cm − 13) ÷ 2

For example, a mother of 165 cm and a father of 180 cm give a boy an estimate of (165 + 180 + 13) ÷ 2 = 179 cm (about 5 ft 11 in). A girl with the same parents comes out at 166 cm (about 5 ft 5 in). The calculator also shows a ±8.5 cm range, because real children rarely land exactly on the midpoint.

You can enter heights in centimetres or feet & inches using the unit toggle, and every result is shown in both units so the numbers make sense whichever way you think about height.

Why the prediction is a range, not a single number

Height is polygenic — hundreds of genes each add a tiny bit — and it is shaped by more than DNA. A child’s final adult height also depends on:

  • Genes inherited from grandparents, not just the parents
  • Nutrition and overall health through childhood
  • Sleep, activity levels, and general wellbeing
  • Timing of puberty and growth spurts
  • A good measure of plain chance

Because of all this, the same formula can be a little high for one sibling and a little low for another. The ±8.5 cm band is there to remind you the estimate is a starting point, not a destiny.

Just for curiosity — when to ask a real expert

This calculator is an entertainment and curiosity tool. It is not a growth assessment and cannot tell you whether a child is growing normally. If you have genuine concerns about your child’s growth — for instance if they seem much shorter or taller than peers, have slowed down or sped up unexpectedly, or you have a family history of growth conditions — those questions belong with your pediatrician.

A doctor can plot your child on proper growth charts, track their pattern over time, and look at the full picture in a way no single formula can. Use this tool for the fun of it, and lean on a healthcare professional for anything that actually matters to their health.

Frequently asked questions

How tall will my child be?
A quick way to estimate is the mid-parental height method: add both parents' heights in centimetres, add 13 cm for a boy or subtract 13 cm for a girl, then divide by two. That gives a single target figure. Real adult height usually lands within about 8.5 cm either side, so our calculator shows a range too. It is a genetics-based ballpark, not a measurement of your child's actual growth.
How accurate is the mid-parental height method?
It gives a reasonable estimate for most children, but the spread is wide — roughly plus or minus 8.5 cm, which is over three inches in each direction. Genes from grandparents, nutrition, sleep, overall health, and plain chance all push the final number around. Treat the prediction as a fun guide, not a guarantee.
Do girls and boys use the same formula?
The structure is the same, but the sex adjustment flips. For a boy you add 13 cm to the combined parent heights before halving; for a girl you subtract 13 cm. That 13 cm reflects the average adult height difference between men and women, so a brother and sister with the same parents get estimates about 13 cm apart.
Can a child be taller than both parents?
Yes, and it is fairly common. Height is influenced by many genes plus environment, so a child can inherit a taller-leaning mix than either parent shows, or simply benefit from better nutrition. That is exactly why the calculator gives a range rather than one fixed number — the real outcome often sits above or below the midpoint.
Does this calculator store any of my data?
No. Everything is worked out in your browser. Nothing you type is sent to a server, saved to a database, or shared with anyone. Refreshing the page clears your inputs completely.

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— The Period Tools Team