Child height predictor
Enter both parents' heights, get the predicted adult height and range.
Measured heights work better than remembered ones. Use biological parents' adult heights.
How is a child's adult height predicted from the parents' heights?
This is the mid-parental, or target height, method of Tanner, Goldstein and Whitehouse (1970). For a boy: (mother's height + father's height + 13 cm) ÷ 2. For a girl: (mother's height + father's height − 13 cm) ÷ 2. The 13 cm (about 5 inches) is the average height difference between adult men and women; it is the same as averaging the parents and then adding 6.5 cm for a boy or subtracting 6.5 cm for a girl.
Example
A mother who is 5 ft 5 in (165.1 cm) and a father who is 5 ft 11 in (180.3 cm) have parents' average of 5 ft 8 in. A son is predicted at 5 ft 10.6 in (179.2 cm), the 63rd percentile among 20-year-old men in the CDC chart; a daughter at 5 ft 5.4 in (166.2 cm), the 67th percentile among women. Another worked example from the literature: parents of 170 cm and 157 cm and a daughter give (170 + 157 − 13) ÷ 2 = 157 cm.
What does the ±8.5 cm range mean?
Tanner and colleagues estimated that a child's adult height should fall within 8.5 cm (3.35 inches) of the target height; the band corresponds to the 3rd and 97th percentiles, so it was meant to hold about 94 of 100 children with parents of those heights. The MSD Manual describes it as about 2 standard deviations around the target. Later work found children vary more than that: one study reports that Tanner himself later widened the band to ±9 cm for girls and ±10 cm for boys, and that a 95% interval on CDC data is about ±10.6 cm for girls and ±11.7 cm for boys. Treat the range as a rough guide, not a guarantee.
How accurate is the prediction?
Only moderately. In a study of 419 children aged 8 to 9, about 90% of heights fell within 1.5 standard deviation scores of the mid-parental height, roughly two percentile lines on a growth chart. When parents are unusually tall or short, their children tend to be less extreme than the average of the parents (regression to the mean), so the method overshoots for tall parents and undershoots for short ones. Heights that parents report themselves are often wrong, usually too high, which is why doctors prefer to measure the parents. Nutrition, illness, the timing of puberty and the fact that children can grow taller than their parents' generation all move the result.
What does the percentile of the predicted height mean?
It compares the predicted height with 20-year-olds of the same sex in the 2000 CDC stature-for-age chart, using the CDC's L, M and S numbers at 240 months: the median is 176.8 cm (69.6 in) for men and 163.3 cm (64.3 in) for women. The chart is built on U.S. surveys from 1963 to 1994, so it is a reference, not today's average: in 2015–2018 U.S. adults 20 and over averaged 175.3 cm (69.0 in) for men and 161.3 cm (63.5 in) for women, a little shorter, which means these percentiles run slightly low against current adults.
Are there better ways to predict height?
Methods that also use the child's own height, weight or bone age can do better. The Khamis–Roche method, for instance, is limited by its authors to white American children without conditions that alter growth, and bone-age methods need an X-ray read by a doctor, so we do not include them. To see how your child is growing now, use the baby growth percentile calculator. A pediatrician compares the child's growth with the target height, and a large gap between them is one of the things doctors look at.
Related: how a young child is growing now, with the baby growth percentile calculator; the child BMI calculator for ages 2 to 19; and the ideal weight calculator for adults.
Sources: Tanner JM, Goldstein H, Whitehouse RH, “Standards for children's height at ages 2–9 years allowing for heights of parents,” Arch Dis Child 1970;45(244):755–762; MSD Manual, “Height Potential: A Child's Target Height Based on Midparental Height”; Zeevi D et al., “Accurate prediction of children's target height from their mid-parental height” (preprint, 2022; it reports the ±8.5 cm range and the later ±9 and ±10 cm and ±10.6 and ±11.7 cm ranges, citing Tanner 1986 and Hermanussen and Cole, Horm Res 2003;59:180–183); Wright CM, Cheetham TD, Arch Dis Child 1999;81:257–260; van Dommelen P, Schönbeck Y, van Buuren S, Arch Dis Child 2012;97:182; Tornese G, Minerva Endocrinol 2022;47:377–378; 2000 CDC Growth Charts data files at cdc.gov/growthcharts (Source: CDC and the National Center for Health Statistics; available there free of charge); Fryar CD et al., NCHS Vital Health Stat 3(46), 2021 (NHANES 2015–2018). This calculator is not endorsed by or affiliated with the CDC, NCHS, HHS or the U.S. government.
For general information only — not medical advice. A prediction from the parents' heights is an estimate, and many healthy children end up taller or shorter than it. Talk with your child's pediatrician or another health professional about your child's growth; this is not a medical tool. How we check our calculators.