Annual Growth Rate
Any interval can be rescaled to a yearly rate for comparison. Between age 3 and puberty, 5–6 cm a year is typical.
Your numbers
Result
8cm
Difference
8cm
What it means
Growing at 8 cm a year.
Formula
Result = (After − Before) ÷ Months × 12
Sustained growth under 4 cm a year is worth a specialist review; during puberty the rate rises to 7–9 cm.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Before (cm)The starting value — it goes in the denominator. | 120 | 1 ~ 250 |
| After (cm)The value you ended up with. | 128 | 1 ~ 250 |
| MonthsThe period counted in months; a yearly rate gets divided by twelve. | 12 | 1 ~ 120 |
Step by step
Quick reference table
Results when only Before (cm) changes and everything else stays put.
| Before (cm) | Result (cm) | Difference (cm) |
|---|---|---|
| 60 | 68 | 68 |
| 90 | 38 | 38 |
| 120 | 8 | 8 |
| 180 | -52 | -52 |
| 240 | -112 | -112 |
What each result means
| Result | At default values |
|---|---|
| Result (cm)What the formula gives back — the answer this page is for. | 8 |
| Difference (cm)The gap between two values — a quantity, not a rate. | 8 |
Common mistakes
Sustained growth under 4 cm a year is worth a specialist review; during puberty the rate rises to 7–9 cm.
Glossary
- Before
- The starting value — it goes in the denominator.
- After
- The value you ended up with.
- Months
- The period counted in months; a yearly rate gets divided by twelve.
- Result
- What the formula gives back — the answer this page is for.
- Difference
- The gap between two values — a quantity, not a rate.
Frequently asked questions
Q. How is Annual Growth Rate calculated?
Result = (After − Before) ÷ Months × 12 — Any interval can be rescaled to a yearly rate for comparison. Between age 3 and puberty, 5–6 cm a year is typical.
Q. Can you walk through an example?
With Before 120cm, After 128cm, Months 12, the answer is Result 8cm.
Q. What do I need to enter?
Enter Before, After, Months. 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 Before (cm) moves the answer to Before (cm) 60 → Result (cm) 68 and Before (cm) 240 → Result (cm) -112. 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?
Sustained growth under 4 cm a year is worth a specialist review; during puberty the rate rises to 7–9 cm.
Related calculators
These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.