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Track your baby's growth with WHO growth standards
0.0th
Below Normal Range - Consult Pediatrician
0.0th
Below Normal Range - Consult Pediatrician
0.0th
Below Normal Range - Consult Pediatrician
0.0th
Below Normal Range - Consult Pediatrician
50th Percentile:
Average - half of babies are larger, half are smaller
25th-75th Percentile:
Normal range - most babies fall in this range
5th-95th Percentile:
Healthy range - growth pattern is more important than exact percentile
Below 5th or Above 95th:
Discuss with pediatrician - may be normal but worth checking
A baby percentile calculator is a medical tool that compares your baby's growth measurements to the World Health Organization (WHO) growth standards. These standards are based on data from thousands of healthy, breastfed babies from around the world. The calculator converts your baby's weight, length, and head circumference into percentiles, which tell you how your baby compares to other babies of the same age and gender. For example, if your baby is in the 60th percentile for weight, it means 60% of babies the same age weigh less, and 40% weigh more. Pediatricians use these percentiles to monitor growth patterns over time, not just single measurements. The WHO standards are considered the gold standard for babies 0-24 months because they represent optimal growth under ideal conditions. This calculator helps parents and healthcare providers identify potential growth concerns early and track development milestones effectively.
Baby percentiles are calculated using the WHO LMS method, which stands for Lambda (skewness), Mu (median), and Sigma (coefficient of variation). First, accurately measure your baby's weight using a calibrated infant scale, length using a length board with the baby lying flat, and head circumference using a flexible measuring tape around the largest part of the head. Record the baby's exact age in completed months and weeks. The calculator then compares these measurements to WHO reference tables that account for age and gender. The LMS formula converts raw measurements into z-scores, which are then translated into percentiles. Weight-for-length percentile is particularly important as it indicates whether a baby's weight is appropriate for their height, independent of age. This helps identify babies who may be underweight or overweight for their size. Most babies will have different percentiles for different measurements, which is completely normal. What matters most is that the baby follows a consistent growth curve over time rather than jumping between drastically different percentiles at each checkup.
| Age | Weight (Boys) | Weight (Girls) | Length (Boys) | Length (Girls) |
|---|---|---|---|---|
| Birth | 7.5 lbs | 7.2 lbs | 19.7 in | 19.3 in |
| 6 months | 17.5 lbs | 16.5 lbs | 26.6 in | 25.8 in |
| 12 months | 21.0 lbs | 19.5 lbs | 29.8 in | 29.2 in |
| 18 months | 24.0 lbs | 22.5 lbs | 32.3 in | 31.7 in |
| 24 months | 27.0 lbs | 25.5 lbs | 34.2 in | 33.7 in |
Any percentile between the 5th and 95th is considered normal. Most babies (about 90%) fall within this range. What matters most is that your baby follows a consistent growth curve over time, not the exact percentile number.
Not necessarily. Babies come in all sizes, and genetics play a major role. If both parents are smaller, the baby may naturally be in a lower percentile. However, if your baby drops significantly across percentiles or falls below the 5th percentile, consult your pediatrician.
Follow your pediatrician's recommended well-baby checkup schedule: typically at 2 weeks, 2 months, 4 months, 6 months, 9 months, 12 months, 15 months, 18 months, and 24 months. Avoid measuring too frequently at home as small variations can cause unnecessary worry.
Weight-for-length percentile shows whether your baby's weight is appropriate for their height, regardless of age. It helps identify babies who may be underweight or overweight for their size and is a better indicator of nutritional status than weight alone.
WHO charts are based on breastfed babies from diverse populations and represent optimal growth. CDC charts are based on a mix of breastfed and formula-fed babies in the US. WHO charts are recommended for babies 0-24 months, while CDC charts are typically used for children 2 years and older.
Baby percentiles are not reliable predictors of adult height. Growth patterns change significantly during childhood and adolescence. Genetic factors and mid-parental height are better predictors of eventual adult stature.
It's completely normal for weight, length, and head circumference to be in different percentiles. Babies have unique body proportions. As long as each measurement follows a consistent curve over time, there's usually no concern.
Breastfed babies often gain weight more rapidly in the first few months, then slow down compared to formula-fed babies. By age 1, growth patterns typically even out. WHO standards are based on breastfed babies as the optimal reference.
For children ages 2-20 years
Calculate body mass index percentile
Track head growth development
Assess newborn weight status
Estimate prenatal growth
Compare height to population
This calculator is for informational purposes only and does not constitute medical advice. Growth percentiles are screening tools that should be interpreted by a qualified healthcare provider. Always consult your pediatrician for personalized medical guidance regarding your baby's growth and development. If you have concerns about your baby's growth pattern, feeding, or overall health, seek professional medical attention promptly.