Child Height Predictor Calculator
This calculator provides an estimate and is not medical advice.
Predicting Adult Height From Two Numbers
Height is strongly heritable, and the mid-parental height method turns that heritability into a rough numeric estimate using nothing more than both parents' heights. It's a decades-old approximation used in pediatric growth screening, not a precision forecast — genetics, nutrition, and individual growth timing all still play a role in where a specific child ultimately lands.
The Formula
Girls: (Father's Height + Mother's Height − 13) / 2
(heights in cm; result has a typical range of ±8.5 cm)
The +13/−13 cm adjustment accounts for the average height difference between adult men and women, translating a same-sex-comparable "mid-parent" figure into a sex-specific prediction for the child.
A Worked Example
For a father at 180 cm and a mother at 165 cm: a son's predicted adult height is (180+165+13)/2 = 179.0 cm (about 5 ft 10.5 in), with a likely range of 170.5–187.5 cm. A daughter's predicted height is (180+165−13)/2 = 166.0 cm (about 5 ft 5.4 in), with a likely range of 157.5–174.5 cm.
Where This Gets Used
- Pediatric growth screening — doctors sometimes use mid-parental height as one reference point when evaluating whether a child's growth trajectory looks proportionate to family genetics.
- General curiosity — a common starting point for parents wondering how tall their child might eventually be.
- Clothing and furniture planning — a loose long-term reference when making decisions like bunk bed or car seat longevity.
How to Use This Calculator
- Enter the father's height and the mother's height.
- Select cm or in as the unit.
- Select the child's sex.
- Select Calculate to see the predicted adult height and likely range.
Related Calculations
Track current growth against age-based norms with the Baby Growth Percentile Calculator, or check current age precisely with the Baby Age in Months Calculator.