Height Calculator

What It Does

This page answers two questions about height on one surface. The prediction direction estimates a child's adult height from the father's and mother's heights, using the mid-parental method, and prints a target range around its midpoint. The percentile direction reads a child's own height at their age and sex against the CDC 2000 Growth Charts' stature-for-age reference and prints the percentile that position corresponds to, with the reference's median height at that age beside it.

Real-World Usage

Parents use the prediction when they want a rough expectation of adult height and a range to weigh it against, often while a child's growth is being discussed. The percentile direction is the one a paediatric appointment uses: a height plotted against a growth reference, at an age, is the ordinary way growth is followed over time. It is also what a coach or a school reaches for when comparing a child with their peers, with the caveat that being tall or short for an age says nothing about how much a child still has to grow.

Local Context

Height is a property of a child and of the reference, not of the country, so one page serves every country and the figures are the same everywhere. Two conventions are worth knowing. The percentile reference here is the CDC's 2000 Growth Charts, stature-for-age tables that are standard in the United States; other countries publish their own growth references, and a percentile read from a different reference can differ by a few points, so follow a child against one reference over time rather than switching between them. And the decimal separator in the input fields is the point, as in 1.75 or 140.5, whatever separator your language uses in ordinary prose; the height inputs themselves can be given in centimetres, metres or feet and inches, and the answer is printed in the unit you chose, in your language's own number format.

How accurate is the mid-parental estimate?

It is a statistical expectation, not a prediction for one child. Roughly two in three children whose parents' heights put the midpoint at 179 cm end up within about 8.5 cm of it, which is why the answer is printed as a range. Childhood growth, nutrition, health and the timing of puberty all move the final figure, and no calculation can see them.

Why does the growth reference stop at 20?

Because that is the range the reference is published for. The stature-for-age tables begin at 24 months, where standing height becomes the measurement of record, and end at 240 months, by which point growth is essentially finished. Below or above that range the table has nothing to say, so the page refuses the age and names the domain instead of extrapolating a curve it does not have.

Does a low percentile mean something is wrong?

Not on its own. A percentile is a position in a reference population, not a diagnosis. A child who has always tracked the 3rd percentile is following their own line, while a child who drops across several percentile lines is the one a clinician looks at. This page measures position only; a concern about growth belongs with a doctor who can plot the trend.

Why do boys and girls get different answers from the same parents?

Because the method adjusts the parents' mean height by a fixed 13 cm for the child's sex — the difference between the average adult heights of men and women in the population the method was derived from. The two parents' heights are the same input in both cases; the adjustment is what makes the answer sex-specific.