Infant Growth Percentile Calculator
Last updated: 2026-06-25
A growth percentile shows where your baby ranks among 100 peers of the same sex and age. This tool estimates height and weight percentiles using the WHO Child Growth Standards (0-24 months).
Between the 3rd and 97th percentile is generally normal. The growth trend matters more than the number; consult your pediatrician for accurate assessment.
Enter your baby's details
Height & weight percentile (estimate)
–
| Item | Value | Percentile |
|---|---|---|
| Height (length) | ||
| Weight |
This result is a reference estimate based on WHO statistics interpolated between months. For accurate growth assessment and interpretation, have your pediatrician plot the growth curve directly.
How to use
- Select sex and age — select your baby's sex and age in months (0-24).
- Enter height and weight — enter the measured height (cm) and weight (kg).
- View the result — press Calculate to see the approximate height and weight percentiles with an interpretation.
How the growth percentile is calculated and interpreted
A growth percentile shows where your baby ranks if you lined up 100 babies of the same sex and age. This calculator uses the LMS statistics (L = skew, M = median, S = coefficient of variation) from the WHO Child Growth Standards to compute a standard score (z-score) and convert it to a percentile of the normal distribution.
z = ((value ÷ M)L − 1) ÷ (L × S) (when L = 1, as for height, z = (value − M) ÷ (M × S))
Percentile (%) = cumulative probability up to z in the standard normal distribution × 100
Percentile interpretation guide
| Percentile | Interpretation |
|---|---|
| Below 3rd percentile | Smaller or lighter than peers — check recommended |
| 3rd-15th percentile | Lower end of normal range |
| 15th-85th percentile | Average range where most babies fall |
| 85th-97th percentile | Upper end of normal range |
| Above 97th percentile | Larger or heavier than peers — check recommended |
What matters is the growth trend, not a single point in time. A low percentile is usually fine if the baby keeps growing along the same curve, while a large shift over a short period may warrant a check. The WHO standards are widely adopted for children under 2, so this basis is appropriate for infants (different national charts are often used after age 2).
For the right formula amount, use the baby formula calculator; for feeding intervals, use the feeding interval calculator. The detailed nutrition guide is in the complete baby feeding guide by month.
Frequently asked questions (FAQ)
What is a growth percentile?
A percentile shows where your baby ranks if you lined up 100 babies of the same sex and age. For example, a weight in the 70th percentile means your baby is about 70th of 100 peers, with 30 heavier and 69 lighter. Between the 3rd and 97th percentile is generally considered the normal range.
Are the percentiles from this calculator accurate?
This calculator uses the LMS statistics from the WHO Child Growth Standards (0-24 months), but it interpolates between months, so the results are approximate reference estimates. An accurate growth assessment should be done by plotting the growth curve at a pediatrician's office.
Is a low (or high) percentile a problem?
The growth trend matters more than the percentile value itself. Even a low percentile such as 3-10 is usually fine if the baby grows steadily along that curve. On the other hand, if the percentile suddenly drops or rises by two or more bands, it may warrant a check, so consult your pediatrician.
Can I use the WHO standards for my baby?
The WHO Child Growth Standards are the international reference adopted for children under 2 years (24 months or younger) in many countries. So the WHO 0-24 month basis used by this calculator is appropriate for infants. Different national charts are often used after age 2, so this tool supports up to 24 months only.
Related calculators & guides
Baby Formula Calculator
Calculate daily and per-feeding amounts from weight and age.
Feeding Interval Calculator
Check the recommended feeding interval and frequency by month.
Vaccine Schedule
Check the standard vaccine schedule from your baby's birth date.
Baby Feeding Guide by Month
Formula amount, feeding interval, and solids in one guide.
Last updated: 2026-06-25