Estimate how tall your child will be as an adult, from parent heights.
Updated Sep 2026Fill in the fields and press Calculate. Every range comes from the sources listed under the tool.
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This tool is for general information only and is not medical advice. Talk to a healthcare professional about results that concern you.
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Sources
- Standards for Children's Height at Ages 2-9 Years Allowing for Height of Parents (Tanner JM, Goldstein H, Whitehouse RH, Arch Dis Child 1970) PubMed Central (PMC), NIH
- Is height determined by genetics?: MedlinePlus Genetics MedlinePlus (NIH National Library of Medicine)
- Predicting a Child's Adult Height American Academy of Pediatrics (HealthyChildren.org)
How Tall Will My Child Be?
This height predictor uses the best quick estimate doctors have, the mid-parental height method, also called the Tanner method. Average the two parents’ heights, then add 6.5 cm (2.5 inches) for a boy or subtract 6.5 cm for a girl. Most children end up within about 8.5 cm (3.5 inches) either side of that number as adults.
Height is one of the most heritable human traits: twin studies across eight countries put genetics at roughly 70 to 90 percent of the final result. The remaining 20 percent comes from childhood nutrition, sleep, overall health, and, to a small degree, luck in which genes each parent passed along. That genetic lottery is why two siblings with the same parents can land on opposite ends of the predicted range.
- Likely range for a boy
- Likely range for a girl
What Actually Influences Growth
- Nutrition: enough protein, calories, calcium, and vitamin D through childhood and puberty
- Sleep: growth hormone is released mostly during deep sleep, which makes regular bedtimes genuinely relevant
- Health: untreated chronic illness or long-running deficiencies can shave off potential
- Puberty timing: early bloomers grow sooner but stop sooner; late bloomers often catch up and pass them
The estimate here is a fun and reasonably grounded projection, but the real authority is your pediatrician’s growth chart, which tracks your child’s own curve over time. A child who consistently follows their percentile line is growing well, whatever the line is.
Frequently Asked Questions
How accurate is the mid-parental height method?
About 90 percent of children land within 8.5 cm of the prediction as adults. It is an honest ballpark, not a promise; the doubling method (doubling height at age 2) has similar accuracy.
Can a child grow taller than both parents?
Yes, and it happens regularly. Better childhood nutrition than the parents had, plus a favorable mix of height genes, produces plenty of children who out-grow both parents.
When do children stop growing?
Girls typically finish within 2 to 3 years after their first period, around age 15. Boys keep going later, usually until 16 to 18. Growth plates closing, confirmed by X-ray if needed, is the definitive end.
Should I worry if my child is the shortest in class?
Not from that fact alone; someone has to be. What matters is steady growth along their own percentile. A child who crosses downward through percentiles, or grows less than 4 to 5 cm a year in mid-childhood, is worth mentioning to the pediatrician.
Sources
- Standards for Children's Height at Ages 2-9 Years Allowing for Height of Parents (Tanner JM, Goldstein H, Whitehouse RH, Arch Dis Child 1970) · PubMed Central (PMC), NIH
- Is height determined by genetics?: MedlinePlus Genetics · MedlinePlus (NIH National Library of Medicine)
- Predicting a Child's Adult Height · American Academy of Pediatrics (HealthyChildren.org)
This predictor is for curiosity and general information. Growth concerns belong with your pediatrician.