Growth Velocity: What Height Change Shows

Growth velocity is a description of change. Take two recorded heights, subtract the earlier from the later, and set that difference against the time between the two dates. The result is a pace for that interval only. It is not a prediction of the next interval, and it is not an adult height.

You need two measurements. One height has a height percentile. It does not have a velocity.

The growth velocity calculator does that arithmetic. Enter the two heights and the two dates. It shows the height change, the number of days between them, and the pace per year. It does not say whether that pace is normal.

How the pace is calculated

The arithmetic uses the two heights and the two dates you recorded. It does not use a required rate. Growth Predictor does not apply a velocity cutoff, and the public height calculator compares a single height with one WHO 2007 height-for-age row. It does not calculate a pace. The growth charts show reference height curves, not a speed a child is supposed to match. The calculator is the place to run the arithmetic. This article is the explanation of what the result does and does not mean.

Why the time between measurements matters

A difference of half a centimeter means something different across two weeks than across six months. The interval is part of the result. A longer interval gives the recorded change more room to stand out from ordinary variation in how someone stands. How often to measure is about leaving that room on purpose.

Why a short interval can mislead

Short intervals are easy to misread. Ordinary variation in posture, time of day, or technique can be as large as the growth that actually occurred, so the pace can look very fast or very slow when little time has passed. That figure is still only a description of the two readings. It is not a diagnosis.

How fast should a child grow?

Children and adolescents do not gain height at one steady rate. Earlier childhood, the years just before puberty, and puberty itself commonly show different paces, and two people of the same age can differ. A number that looks modest at one stage can be ordinary at another.

This article does not list cutoff rates. Growth Predictor does not turn a pace into a forecast of how much height is still ahead.

A series is more useful than one pace

A single pace is only as good as its two endpoints. If either height was measured loosely, the pace inherits that. A series of measurements, taken the same way, shows whether later intervals look similar or different. That history is context. It is a record of the past, not a promise about adult height.

You can compare any one of those heights with the reference. The percentile answers a different question from the pace: where this height sits for this age and sex, not how fast the last interval was. Both can be worth knowing. Neither replaces the other, and neither is a grade.

Common questions

Can one measurement show growth velocity?

No. Velocity needs two dated heights. A single height can have a percentile, and it cannot have a pace.

Is a fast pace a prediction?

No. It describes the interval that was recorded. It does not say what the next interval will be, and it is not an adult height.

Do the growth charts show a required growth rate?

No. They show reference heights by age. They are not a rate a child is supposed to match.