Adult Height Predictor

A fun, classic estimate of how tall your kid might grow up to be — using parents' heights, or a toddler's current height.

Most accurate around age 2 (boys) or 18 months (girls).
Estimated adult height
lower estimate
higher estimate
Both methods are population-level approximations for fun, not medical predictions — actual adult height depends on nutrition, health and genetics beyond just parents' heights or a single toddler measurement, and results can be off by several centimeters (a couple of inches) either way.

Common questions

How accurate is a height predictor?

Both methods here are rough estimates, generally accurate to within a few centimeters (roughly 2–4 inches) for most children, but individual results vary — genetics plays the largest role, but nutrition, health and puberty timing all shift the outcome too.

What is the mid-parental height method?

It averages both parents' heights and adjusts by about 13cm (5 inches) up for boys or down for girls, reflecting the average height difference between men and women — a formula pediatricians have used informally for decades as a rough target range.

What is the "double the height at age 2" rule?

It's an old rule of thumb that a child's adult height is roughly double their height at exactly age 2 for boys, or around 18 months for girls — based on the observation that roughly half of adult height is reached by around that age. It's less reliable the further the measurement is taken from that specific age.

Does a child's sex affect the prediction?

Yes — both methods here ask for the child's sex because average adult height differs between men and women by roughly 13cm (5 inches), which is built into the mid-parental height adjustment and reflected in when the doubling rule is best applied.

What actually determines how tall my child will be?

Genetics is the biggest factor, generally estimated to account for the majority of height variation between people, with nutrition, overall health, sleep and chronic illness able to shift a child below their genetic potential if problems go unaddressed. A pediatrician tracking your child's own growth curve over time gives a much better picture than any single-point prediction.

Does "how tall will my kid be" mean the same thing as this calculator?

Yes — "kid," "child" and "toddler" all refer to the same estimate here. Whichever word you'd naturally use, pick the method above that matches what you currently know (both parents' heights, or your toddler's current height around age 2).