Height Calculator

Predict adult height from current child height or parents' heights using the mid-parental height method.

ft
in
yrs
mo

Predicted Adult Height

5' 4"

162.8 cm

Child is currently at 78.0% of predicted adult height

How to Use the Height Calculator

This calculator offers two tools for predicting adult height:

  1. Child Height Predictor: Enter the child's current measured height and age. The calculator uses CDC growth chart percentile data to estimate what percentage of adult height the child has reached, then extrapolates to 18 years. Works for children aged 2 to 17.
  2. Parents Height Method (mid-parental height): Enter the heights of both biological parents. The calculator applies the standard formula to estimate the child's target height range based on genetics. This is independent of the child's current age.
Height prediction methods are estimates, not guarantees. Nutrition, sleep, health, and genetics all interact to determine final height. Individual variation around any prediction can be plus or minus 2 to 4 inches. Bone age X-ray studies by a pediatric endocrinologist give the most accurate prediction.

Height Prediction Formulas

Mid-parental height method (also called the Tanner method) is the simplest and most widely used approach:

Boys:  Predicted height = (Father's height + Mother's height + 5 in) / 2
Girls: Predicted height = (Father's height + Mother's height - 5 in) / 2

The 5-inch adjustment (13 cm) accounts for the average height difference between adult men and women.

Example: Father is 5'10" (70 in), mother is 5'4" (64 in), predicting for a boy:

Predicted = (70 + 64 + 5) / 2 = 139 / 2 = 69.5 inches = 5'9.5"

Growth chart method uses the current height as a percentage of adult height based on age and sex data from CDC growth charts:

Predicted adult height = Current height / Growth factor at current age

For example, a 10-year-old boy at 78% of adult height who is currently 4'10" (58 inches):

Predicted = 58 / 0.780 = 74.4 inches = 6'2"

Frequently Asked Questions

The mid-parental height method predicts adult height within 2 inches (5 cm) for about 95% of children. The growth chart method has similar accuracy but requires knowing the child's current height and age precisely. The only way to significantly improve accuracy is a bone age study, which uses an X-ray of the left hand and wrist to assess skeletal maturity.

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