Child Height Predictor
Predict a child's adult height from the parents' heights.
Predicted adult height
179 cm
5′ 10″
Range (±8.5 cm)
171–188 cm
In feet/inches
5′ 10″
AI Breakdown & Smart Takeaway
Plain-English insight on your numbers
Get a personalized explanation of what these results mean — and how to improve them.
How the Child Height Predictor works
The Child Height Predictor estimates a child's likely adult height based on the heights of both biological parents, using clinically recognized formulas that account for sex-specific growth patterns. It's designed for parents, pediatricians, and caregivers who want a data-driven benchmark for healthy childhood development.
The calculator uses the mid-parental height (MPH) method, one of the most widely validated clinical tools for predicting adult stature. This approach averages the heights of both biological parents and then applies a sex-specific correction factor — adding approximately 2.5 inches (6.5 cm) for boys or subtracting 2.5 inches for girls — to account for the average height difference between adult males and females. The result represents the child's target height, and a prediction range of roughly ±4 inches (±10 cm) around that target captures about 95% of children raised in healthy environments.
The mid-parental formula works because height is a strongly polygenic trait — meaning it is governed by hundreds of genes inherited from both parents. Research consistently shows that parental height explains roughly 60–80% of a child's eventual adult height, making it by far the single strongest predictor available without genetic testing. The calculator operationalizes this hereditary signal quickly and reliably, offering an estimate that closely aligns with what a pediatric growth chart follow-up would project over many years of tracking.
The remaining 20–40% of height variation is shaped by environmental and biological factors: nutrition (especially adequate protein, calcium, and vitamin D during growth spurts), sleep quality (since growth hormone is primarily secreted during deep sleep), chronic illness or medication use, and the timing of puberty. Children who experience early puberty may grow faster initially but often end up shorter than predicted, while late bloomers may appear shorter in adolescence yet reach or exceed their predicted height. The calculator's output is therefore best understood as a genetic ceiling estimate — the height a child is likely to reach under optimal conditions.
A common mistake is treating the prediction as a guaranteed outcome rather than a probabilistic range. The ±4-inch window around the target height is meaningful: a boy with a predicted height of 5'10" could reasonably end up anywhere from 5'6" to 6'2" and still fall within normal biological variation. Additionally, the formula assumes both parent heights are reported accurately in the same unit system — entering one parent's height in feet and the other in centimeters without conversion will skew results significantly. For the most clinically grounded assessment, compare the calculator's output against your child's current position on a CDC or WHO growth chart, which tracks actual trajectory over time.
Formula
Mid-parental: (mother + father ± 13 cm) / 2
Pro tips
- Enter both parents' heights as accurately as possible — even a 1-inch error in a parent's reported height shifts the child's prediction by half an inch, which can move a child across a meaningful growth percentile boundary.
- Use the predicted height range, not just the single midpoint number: share the full ±4-inch window with your pediatrician so they can flag any child growing persistently below the lower bound for further evaluation.
- Track your child's actual height on a CDC or WHO growth chart alongside this prediction — a child consistently crossing downward through major percentile lines warrants medical review regardless of what the formula shows.
- Optimize the environmental factors within your control: ensure your child gets 9–11 hours of quality sleep per night (the primary window for growth hormone release), eats sufficient protein and calcium, and stays physically active, all of which support reaching the genetic ceiling this calculator estimates.
- Remember that puberty timing shifts the trajectory — if your child is an early or late developer, discuss bone age assessment with a pediatrician for a more refined adult height prediction than the parental-height formula alone can provide.
Key terms
- Mid-Parental Height (MPH)
- — The average of both biological parents' heights, adjusted by a sex-specific factor, used as the primary estimate of a child's genetically expected adult stature.
- Target Height Range
- — The ±4-inch (±10 cm) window around the mid-parental height prediction within which approximately 95% of children are expected to fall as adults.
- Growth Percentile
- — A child's height ranking relative to peers of the same age and sex, plotted on a standardized growth chart to track developmental trajectory over time.
- Growth Hormone
- — A pituitary-secreted hormone that drives longitudinal bone growth and is released most abundantly during deep sleep, making sleep quality a key environmental factor in reaching predicted height.
- Polygenic Inheritance
- — The genetic mechanism by which height is determined — hundreds of genes from both parents each contribute small effects, collectively accounting for 60–80% of adult height variation.
- Bone Age
- — A radiological assessment of skeletal maturity based on wrist X-ray, often compared to chronological age to refine height predictions in clinical settings beyond what a parental-height formula alone provides.
