Child Height Predictor Calculator

What a mid-parental estimate tells you

This calculator uses the heights of both parents and the selected sex of the child to produce a rough adult-height estimate. The method is often called the mid-parental method: it starts with the parents’ combined heights, adjusts for the selected sex, and divides by two. It is a family-height reference, not a prediction based on the child’s own growth record.

Enter heights in centimeters. The page displays a center estimate and a separate band extending 5 cm below and above it. That ±5 cm band is the calculator’s fixed display rule; it is not a clinically validated confidence interval or a boundary for normal growth. The American Academy of Pediatrics describes the mid-parental method as a very rough estimate and notes that adult height cannot be predicted completely accurately. AAP guidance on estimating a child’s adult height (updated September 30, 2026; checked October 2, 2026).

The two formulas and a worked example

For a father who is 178 cm and a mother who is 165 cm, the boy formula gives (178 + 165 + 13) ÷ 2 = 178 cm, with a displayed band of 173–183 cm. For a girl with the same parent heights, (178 + 165 − 13) ÷ 2 = 165 cm, with a displayed band of 160–170 cm. The page formats the center and band endpoints to one decimal place, so whole-number inputs may appear with “.0”.

These are arithmetic outputs from the selected formula. The band should not be read as a probability range or a clinical target.

Enter heights and read the result

1. Use centimeters for both parents

   Enter each parent’s adult height as a number in centimeters. Convert feet and inches before entering them; the form does not provide an imperial-unit selector.

2. Select boy or girl

   The selection determines whether the formula adds or subtracts 13 before dividing by two. Changing the selection recalculates the result.

3. Check the center and displayed band

   Read the “Genetic Height” value as the formula’s center estimate, then read “Predicted Range” as the page’s fixed five-centimeter band on either side. Clear empties the parent-height fields; enter both values again to restore a result.

For instance, enter 178 for the father, 165 for the mother, and choose Boy to reproduce the 178.0 cm center estimate and 173.0–183.0 cm displayed band shown above.

Questions about the estimate

Keep the estimate in perspective

This calculator performs a parent-height formula only. It does not assess an individual child’s growth or provide medical advice.

• The result depends only on the two entered heights and the selected boy or girl formula. Age, present height, growth over time, bone age, puberty, health conditions, and other clinical details are not included.
• The displayed ±5 cm band is a presentation choice, not a guaranteed outcome, an error limit, a validated confidence interval, or a definition of healthy height. A real adult height may fall outside it.
• A displayed number does not confirm that the entered measurements are accurate or appropriate. Use adult heights in centimeters and check for typing or conversion errors.
• If you are concerned about a child’s growth, discuss dated measurements and the child’s history with a pediatrician. The AAP describes tracking growth over time as part of assessment; CDC notes that growth charts support an overall clinical impression and are not a sole diagnostic instrument.