Calculator Woosh

Health • Height

Height Calculator

Predict a child’s adult height with Tanner mid-parent target (±8.5 cm) and Khamis-Roche (without bone age) using age, current height, weight and parents’ heights.

Child’s sex

Tanner — mid-parent target

—

Khamis-Roche (without bone age)

—

Details

Tanner: Boys (Father+Mother+13)/2, Girls (Father+Mother−13)/2 ±8.5 cm. Khamis-Roche (1994 corrected 1995, Fels): B₀+b₁H+b₂W+b₃MP (H in, W lb, MP avg). 68% margin ±5.6 cm boys / ±4.3 cm girls. Valid 4–17.5y both sexes (erratum).

How to use

  1. 1Choose the child’s sex and decimal age (e.g., 10.5 for 10y6m). Age range for Khamis-Roche is 4–17.5 boys, 4–16.5 girls.
  2. 2Enter current height and weight (switch kg/lb, cm/in) and both parents’ heights.
  3. 3See Tanner target + range and Khamis-Roche prediction with 68% margin (±5.6 cm boys / ±4.3 cm girls).

Formulas

Tanner: Boys (Father+Mother+13)/2 • Girls (Father+Mother−13)/2 • Khamis-Roche: B₀+b₁H(in)+b₂W(lb)+b₃MP(in)

Tanner is simple and valid at any age (≈95% within ±10 cm). Khamis-Roche 1994 is more accurate at 4–14y using regression without an X-ray; coefficients are sex/age-specific and interpolated for fractional ages.

Examples

Boy, 10y, 140cm, 35kg, father 175cm, mother 162cm

Tanner 175 cm (Range 166.5–183.5) • Khamis-Roche ~174 cm (±5.6) reflecting percentile.

Tanner 175 • Khamis ~174

Girl, 9y, 135cm, 30kg, father 180cm, mother 165cm

Tanner (180+165−13)/2=166 cm • Khamis ~164 cm (±4.3).

Tanner 166 • Khamis ~164

About

The Height Calculator predicts a child's adult height using two established methods: the Tanner mid-parental target and the Khamis-Roche technique, which does not require a bone-age X-ray. Enter the child's sex, age, height, weight, and both parents' heights to receive a predicted adult height with a realistic range. Parents and pediatric care teams use these estimates for routine growth monitoring and to identify children who may fall outside expected ranges. The predictions are statistical estimates with margins of error, and unusual growth patterns should be discussed with a pediatrician.

Frequently asked questions

Why do the two methods differ?
Tanner uses only parents (genetic target). Khamis-Roche blends the child’s current size + weight + parents, so tall-for-age children predict higher.
How accurate is this?
Tanner ±8.5 cm covers most children; Khamis-Roche 68% within ±5.6 cm (boys) / ±4.3 cm (girls), growing to ~±10 cm at 95%. Nutrition, health and timing of puberty also matter.
Can I use it for adults?
No — once growth plates close, height is set. This is for children still growing.

Disclaimer

Educational estimates only, not medical advice. For growth concerns see a pediatrician. Khamis-Roche validated on U.S. reference children.

Related calculators

Calorie Calculator
BMR & TDEE
Volume Calculator
Cube, cylinder, sphere…