Adult Height Predictor
Use this height prediction calculator to estimate how tall a child may be as an adult. It uses the mid-parental height method and can optionally adjust using the child’s current age and height.
Note: This is an estimate, not a diagnosis. Genetics, puberty timing, nutrition, sleep, and medical conditions can all affect final adult height.
What this “how tall you will be” calculator does
This tool gives a practical estimate of adult height using a common pediatric approach called the mid-parental height formula. It is often used as a quick screening method in clinics and at home. You enter the mother’s and father’s heights, choose whether the child is a boy or girl, and the calculator returns a predicted adult height plus a likely range.
If you also enter the child’s current age and height, the calculator applies a light growth-position adjustment. That extra step can make results feel more personalized, especially for children who are currently much taller or shorter than average for their age.
How the height prediction is calculated
1) Mid-parental height formula
- For boys: (Father’s height + Mother’s height + 13 cm) ÷ 2
- For girls: (Father’s height + Mother’s height − 13 cm) ÷ 2
The same formula in imperial units uses ±5 inches instead of ±13 cm. This gives the core estimate for adult height.
2) Optional growth-position adjustment
When age and current height are provided, the calculator compares the child’s present height to a typical median height for that age and sex. If the child is currently above or below median, the estimate is adjusted modestly. This is not a full bone-age or endocrinology model, but it helps refine the baseline.
3) Predicted range
Instead of showing only one number, the calculator also displays a likely range around the estimate (about ±8.5 cm or ±3.3 inches). Real growth is variable, so a range is more realistic than a single point.
Why your final adult height may differ
Even the best online height predictor cannot account for every biological factor. Final height can shift due to:
- Genetics beyond parents: grandparents and extended family influence height too.
- Puberty timing: early or late puberty can temporarily change growth patterns.
- Nutrition: consistent intake of calories, protein, vitamins, and minerals matters.
- Sleep quality: growth hormone is tied to healthy sleep cycles.
- Medical conditions: endocrine, gastrointestinal, and chronic illnesses can affect growth.
- Physical activity: active lifestyles support general growth and bone health.
How to measure height correctly
Good inputs improve output. For best accuracy:
- Measure without shoes.
- Stand straight with heels against a wall.
- Look forward (not up or down).
- Use a flat object on top of the head and mark the wall.
- Measure at the same time of day when possible.
Frequently asked questions
Is this calculator accurate?
It is a reasonable estimate tool, not a guarantee. Most users should treat the predicted number as a center point and focus on the displayed range.
Can adults use this calculator?
The tool is designed for estimating a child’s future adult height. Adults who have completed growth won’t gain useful prediction value.
Does this replace a pediatrician visit?
No. If a child’s growth curve changes suddenly, falls far below expected percentiles, or if there are concerns about puberty timing, consult a pediatrician or pediatric endocrinologist.
Bottom line
This “how tall you will be calculator” is a quick, practical way to estimate adult height using parent heights, sex, and optional current growth data. It is ideal for educational use, family planning conversations, and general curiosity. For medical decisions, always rely on professional growth tracking and clinical advice.