Khamis-Roche method height calculator
The Khamis-Roche method predicts adult height from four things: current age, height, weight and the average of the parents’ heights. It needs no X-ray and covers ages 4 to 17.5. In the 1994 study that introduced it, 90% of predictions landed within ±5.3 cm (2.1 in) for boys and ±4.3 cm (1.7 in) for girls. Enter the four inputs below. This is an estimate, not medical advice.
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Khamis-Roche prediction
Enter the four inputs and press Predict with Khamis-Roche.
What is the Khamis-Roche method?
It is a statistical way to predict adult height, published by Harry Khamis and Alex Roche in Pediatrics in 1994, with a correction in 1995. Older methods relied on “bone age” read from a hand X-ray. Khamis and Roche showed that a prediction built only from measurements a parent can take at home came reasonably close to those X-ray methods in their study group.
The Khamis-Roche formula
adult height = intercept + (a × height) + (b × weight) + (c × mid-parent height)
The intercept and the three multipliers a, b, c change with age (in half-year steps) and with sex, and come from the tables in the paper. The published tables work in inches and pounds; this calculator converts metric inputs automatically and interpolates between half-year rows. Mid-parent height here is the plain average of the two parents, with no sex adjustment.
Khamis-Roche accuracy
The paper reports a 90% error bound of about ±2.1 in (5.3 cm) for boys and ±1.7 in (4.3 cm) for girls. Put plainly: in the study group, nine predictions in ten were within that distance of the real adult height, and one in ten was further off. The calculator shows that band around every result. It is one of the more accurate methods that does not need an X-ray, but it is not the most accurate method overall; see which height predictor is most accurate.
Limits you should know
- Ages 4 to 17.5 only. For younger children use the baby height predictor or the mid-parental height calculator.
- Built from one study population. The data came from white US children in the Fels Longitudinal Study. Accuracy in other populations may be lower.
- Healthy children only. It does not account for growth disorders, long-term illness or very early or late puberty.
- Our implementation. The coefficient tables here were cross-checked against two worked examples and two independent open implementations, not against every digit of the original printed tables.
Common questions
- Khamis-Roche vs mid-parental height: which is better?
- Mid-parental uses only the parents’ heights and has a target range of about ±8.5 cm. Khamis-Roche adds the child’s own height and weight and reported a narrower 90% band (about ±4–5 cm). When you have the measurements, Khamis-Roche is usually the tighter estimate.
- Do I need a doctor or an X-ray?
- No. A bone-age X-ray is a separate clinical method that a doctor may order when there is a medical concern.
- Why does it ask for weight?
- Weight is one of the four terms in the published equation. Leaving it out would be a different, untested formula.
Primary source: Khamis HJ, Roche AF. “Predicting adult stature without using skeletal age: the Khamis-Roche method.” Pediatrics. 1994;94(4):504–507; erratum 1995;95(3):457. See About for all citations.