Growth Velocity
Divide the height gain by the months and multiply by twelve. Velocity matters more than absolute height: a small child growing at the right speed is fine, while a tall one whose speed drops needs a look.
Your numbers
Growth velocity
6cm/yr
Difference
6cm
Change
5.36%
What it means
6 cm a year is inside the school-age normal band of 5–7 cm.
Formula
Growth velocity = (Height now (cm) − Height then (cm)) ÷ Months between × 12
Use at least six months between measurements, ideally a year. Over short gaps, measurement error swamps the signal.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Height then (cm) (cm)The height measured last time — the starting point for velocity. | 112 | 30 and up |
| Height now (cm) (cm)The height measured now; measure at the same time of day. | 118 | 30 and up |
| Months between (mo)How many months passed between measurements. | 12 | 1 ~ 60 |
Step by step
Quick reference table
Results when only Height then (cm) (cm) changes and everything else stays put.
| Height then (cm) (cm) | Growth velocity (cm/yr) | Difference (cm) | Change (%) |
|---|---|---|---|
| 56 | 62 | 62 | 110.71 |
| 84 | 34 | 34 | 40.48 |
| 112 | 6 | 6 | 5.36 |
| 168 | -50 | -50 | -29.76 |
| 224 | -106 | -106 | -47.32 |
What each result means
| Result | At default values |
|---|---|
| Growth velocity (cm/yr)Centimetres a year; this speed matters more than absolute height. | 6 |
| Difference (cm)The gap between two values — a quantity, not a rate. | 6 |
| Change (%)How far it moved, measured against the before value. | 5.36 |
Common mistakes
Use at least six months between measurements, ideally a year. Over short gaps, measurement error swamps the signal.
Glossary
- Height then (cm)
- The height measured last time — the starting point for velocity.
- Height now (cm)
- The height measured now; measure at the same time of day.
- Months between
- How many months passed between measurements.
- Growth velocity
- Centimetres a year; this speed matters more than absolute height.
- Difference
- The gap between two values — a quantity, not a rate.
- Change
- How far it moved, measured against the before value.
Frequently asked questions
Q. How is Growth Velocity calculated?
Growth velocity = (Height now (cm) − Height then (cm)) ÷ Months between × 12 — Divide the height gain by the months and multiply by twelve. Velocity matters more than absolute height: a small child growing at the right speed is fine, while a tall one whose speed drops needs a look.
Q. Can you walk through an example?
With Height then (cm) 112cm, Height now (cm) 118cm, Months between 12mo, the answer is Growth velocity 6cm/yr.
Q. What do I need to enter?
Enter Height then (cm), Height now (cm), Months between. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Height then (cm) (cm) moves the answer to Height then (cm) (cm) 56 → Growth velocity (cm/yr) 62 and Height then (cm) (cm) 224 → Growth velocity (cm/yr) -106. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Use at least six months between measurements, ideally a year. Over short gaps, measurement error swamps the signal.
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