Calculate your baby's weight percentile using WHO and CDC growth standards. Track healthy weight development and compare your infant's weight to other babies of the same age and gender.
Enter age from 0 to 36 months
WHO recommended for 0-2 years, CDC for 2+ years
Weight percentiles show how your baby's weight compares to other babies of the same age and gender. These measurements help healthcare providers monitor growth patterns and identify potential concerns early.
If your baby is in the 60th percentile for weight, it means 60% of babies the same age and gender weigh less, and 40% weigh more. This is a statistical comparison, not a judgment of health.
A single percentile measurement provides limited information. What's more important is your baby's growth trajectory over time. Healthy babies typically follow their own percentile curve consistently, whether it's the 10th, 50th, or 90th percentile.
The World Health Organization standards are based on healthy, breastfed babies from diverse populations worldwide. They represent optimal growth under ideal conditions.
The CDC growth charts are based on data from US children and include both breastfed and formula-fed babies. They reflect actual growth patterns in the US population.
Babies typically lose 5-10% of birth weight in the first week, then regain it by 2 weeks. Average weights (50th percentile):
Expected gain: 5-7 oz (140-200g) per week in first 3 months, then 4-5 oz (110-140g) per week.
Weight gain slows as babies become more active:
Expected gain: 2-4 oz (60-110g) per week. Most babies triple their birth weight by 12 months.
Weight gain continues to slow as toddlers focus on motor development:
Expected gain: About 3-5 lbs (1.4-2.3 kg) per year after age 2.
Birth weight significantly influences early growth patterns. Larger babies tend to remain larger, while smaller babies often stay smaller. Parents' body types also play a major role—tall, heavy parents typically have larger babies.
Breastfed babies often gain weight more rapidly in the first 3-4 months, then more slowly afterward, resulting in leaner body composition. Formula-fed babies may have steadier weight gain throughout infancy. Both patterns are healthy when babies are thriving.
As babies become more mobile—rolling, crawling, walking—they burn more calories and weight gain slows. This is normal and expected. Very active babies may be leaner than less active peers.
Premature babies are plotted using corrected age (adjusted for weeks early) until age 2-3. They often catch up to full-term peers by age 2, though some remain smaller. Catch-up growth is typically rapid in the first year.
While most variations in baby weight are normal, certain patterns warrant medical evaluation. Contact your pediatrician if you notice:
Respond to your baby's hunger cues rather than following a strict schedule. Newborns typically feed 8-12 times per day. As they grow, feeding frequency decreases but volume increases.
Adequate feeding is reflected in diaper output: 6+ wet diapers and 3-4 dirty diapers per day in the first month. After 6 weeks, stool frequency varies widely but urine output should remain consistent.
Start solid foods around 6 months when baby shows readiness signs. Breast milk or formula remains the primary nutrition source until 12 months. Solids complement, not replace, milk feedings.
Attend all well-child visits for professional weight monitoring. Pediatricians track growth over time and can identify concerns early. Don't rely solely on home measurements for medical decisions.
For healthy babies, weighing at pediatric visits is sufficient. Frequent home weighing can cause unnecessary anxiety. If your doctor recommends monitoring weight, follow their specific guidance.
Rapid weight gain in the first 6 months is usually normal, especially for breastfed babies. Concern arises if baby rapidly crosses multiple percentile lines upward or is consistently above the 97th percentile with other risk factors.
Not necessarily. If your baby is consistently following their own growth curve (even if it's the 10th percentile), meeting developmental milestones, and appears healthy, they're likely fine. Small parents often have smaller babies.
After 3-4 months, breastfed babies often weigh less than formula-fed babies but are leaner and healthier in body composition. WHO standards are based on breastfed babies and represent optimal growth.
Most babies triple their birth weight by 12 months and quadruple it by 24 months. This is a general milestone, and individual variation is normal based on birth weight and genetics.
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