Baby Weight Chart by Month — Birth to 36 Months
CDC growth chart data showing average weight and all percentiles for boys and girls, in both kg and lb
Weight by Month — Birth to 36 Months (Infant)
Weight in kg at each percentile. 50th percentile = average. The right-most column shows the average in lb. Rows with links go to detailed percentile pages for that age.
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Weight by Age — 2 to 20 Years (Child & Adolescent)
These values use the CDC weight-for-age reference data for children 2 years and older, measured in standing position. Values in kg with average in lb.
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Get Your Child's Exact Percentile
Enter your child's weight and age for a personalized percentile score with interpretation.
Calculate Weight Percentile →How to Read This Weight Chart
This chart shows baby weight percentiles from the CDC growth reference data. Each column represents a percentile — the percentage of children who weigh less than that value at the same age.
- 50th percentile = average. Half of children weigh more, half weigh less.
- 25th percentile = 25% of children weigh less. Still perfectly normal.
- 90th percentile = heavier than 90% of same-age children. Also normal.
- 3rd–97th = the full normal range. Being anywhere in this range is healthy.
Baby Weight Milestones
Here are the key weight milestones most parents track:
- Birth weight recovery: Newborns lose 5–10% of birth weight in the first few days and typically regain it by 10–14 days.
- Double birth weight: Most babies double their birth weight by 4–5 months.
- Triple birth weight: Most babies triple their birth weight by 12 months (1 year).
- Quadruple birth weight: Most children reach 4x birth weight by around 2 years.
When Growth Slows Down
After the rapid weight gain of the first 3 months (about 150–200 g/week), growth naturally slows. By 6–12 months, gains slow to about 70–100 g/week. After the first birthday, toddlers gain only about 2–3 kg per year. This slowdown is completely normal and often comes with decreased appetite — don't worry if your toddler eats less than they did as a baby.
Tracking Weight Over Time
A single weight measurement is less important than the trend over time. Use our growth tracker to log multiple measurements and see whether your child is following their growth curve consistently. Our growth velocity calculator can show the rate of weight gain between visits.
Boys vs Girls Weight Differences
Boys are slightly heavier than girls at every age, starting from birth. The difference is small in infancy (about 0.1–0.3 kg) and gradually widens. This is why growth charts always have separate curves for boys and girls. Use the toggle above to switch between the two.
When to Talk to Your Pediatrician
Consult your pediatrician if:
- Your baby drops across two or more major percentile lines
- Weight is consistently below the 3rd or above the 97th percentile
- Weight and height percentiles are very different (e.g., 95th for weight but 15th for height)
- Your baby hasn't regained birth weight by 2 weeks
Learn more in our when to worry about growth guide.
Related Charts & Calculators
Frequently Asked Questions
Baby weight varies by age and sex. At birth, the average boy weighs about 3.5 kg (7.7 lb) and the average girl about 3.4 kg (7.5 lb). By 6 months, averages are 8.2 kg (18 lb) for boys and 7.5 kg (16.4 lb) for girls. By 12 months, averages reach 10.2 kg (22.4 lb) for boys and 9.4 kg (20.6 lb) for girls. See the full percentile table above for every month.
Any percentile from 3rd to 97th is considered within the normal range. What matters most is that your baby grows consistently along their own curve over time. A single measurement at the 10th percentile is just as healthy as one at the 90th, as long as the pattern is stable.
Most babies double their birth weight by 4–5 months and triple it by 12 months. These are averages — some healthy babies reach these milestones a bit earlier or later. Use our weight-for-age calculator to see where your baby falls on the growth chart.
Temporary slowdowns in weight gain are normal, especially after 3 months when growth naturally slows. However, if your baby drops across two or more major percentile lines, is consistently below the 3rd percentile, or shows signs of failure to thrive, consult your pediatrician. Our growth velocity calculator can help you measure weight gain rate.
Yes, on average boys weigh slightly more than girls at every age. The difference is about 0.1 kg at birth and widens to about 0.5–0.8 kg by 12 months. This is why growth charts have separate curves for boys and girls. Use the toggle above to switch between the two.
The WHO growth standards are recommended for children 0–2 years (based on breastfed infants), while CDC charts are used for 2–20 years in the United States. The data on this page uses CDC reference values. Learn more in our CDC vs WHO growth charts guide.
Disclaimer: Data from the CDC Growth Charts. These are population reference values, not targets. Every child grows at their own pace. This is not medical advice — always consult your pediatrician with specific concerns about your child's growth.