👶 Baby Growth Percentile Calculator

1. Enter your baby’s age in months (0–24).
2. Select your baby’s sex (male or female).
3. Enter the weight in kilograms or pounds.
4. Enter the body length in centimetres or inches.
5. Enter the head circumference in centimetres or inches.
6. Click Calculate to see the percentiles for each measurement.

What percentile should my baby be at?

There is no single correct percentile. Babies come in different sizes, and any percentile from the 5th to the 95th is generally considered within the normal range. What matters most is consistency: a baby who stays near the same percentile over time is following their own growth curve, which is a sign of healthy growth. A sudden drop or jump across two or more percentile lines warrants a conversation with your paediatrician.

What is the difference between WHO and CDC growth charts?

The WHO charts are based on optimal growth conditions (breastfeeding, good nutrition, healthy environment) and describe how children should grow. The CDC charts are based on the actual US population and describe how children do grow. For children under 2, the WHO charts are recommended worldwide. For children over 2, many countries use CDC or national references.

Should I worry if my baby is in a low percentile?

Not necessarily. If your baby is consistently in the 10th percentile and growing steadily along that curve, they may simply be a smaller baby, which is perfectly normal. However, a baby who drops from the 50th to the 10th percentile over a short period may need evaluation. Always discuss growth concerns with your paediatrician, who can assess the full picture including feeding, development and overall health.

How accurate are the percentile estimates?

This calculator provides estimates based on simplified WHO reference data. For clinical decisions, your paediatrician uses the full WHO growth charts with exact z-score tables. The estimates from this tool are intended for informational purposes and should not replace professional medical assessment. Always use the same growth charts your healthcare provider uses for consistency.

When tracking your baby’s growth, the most important thing to remember is that the trend matters more than any single number. A baby who is consistently in the 15th percentile for weight and is feeding well, producing enough wet nappies, and meeting developmental milestones is likely growing perfectly normally. On the other hand, a baby who crosses two or more percentile lines (up or down) over a short period may need evaluation, even if the new percentile is still within the normal range. Growth charts are most useful when plotted over multiple visits: your paediatrician maintains a growth curve from each check-up and looks for consistent patterns. Do not compare your baby to other babies: percentiles compare your baby to a statistical reference population, not to the baby next door. Breastfed and formula-fed babies have different growth patterns: breastfed babies tend to gain weight faster in the first 2–3 months and then slower thereafter, which is normal and reflected in the WHO charts. If you are concerned about your baby’s growth, keep a record of feeding patterns (frequency, amount, duration for breastfeeding), wet and dirty nappies per day, and overall behaviour (alertness, activity, sleep). This information, combined with growth percentiles, gives your paediatrician a complete picture of your baby’s health.