Weight Chart for 9-Year-Old Boys
Selected body weight percentiles for boys at 9 years, reported in kilograms and pounds from the cited official reference table.
CDC percentile table
| Percentile | Metric | US customary |
|---|---|---|
| 3rd | 22.1 kg | 48.7 lb |
| 5th | 22.7 kg | 50.1 lb |
| 10th | 23.8 kg | 52.4 lb |
| 25th | 25.8 kg | 56.9 lb |
| 50th | 28.7 kg | 63.2 lb |
| 75th | 32.4 kg | 71.4 lb |
| 90th | 36.9 kg | 81.3 lb |
| 95th | 40.4 kg | 89.0 lb |
| 97th | 43.1 kg | 94.9 lb |
What these numbers imply
The figures below are not published directly by the CDC. Each one is calculated from the official weight-for-age tables so that this page answers questions the raw dataset leaves open. Values differ for every age and sex.
| Measure | Value | How it was derived |
|---|---|---|
| Weight gain over the next 12 months | +3.4 kg | The 50th percentile rises from 28.7 kg to 32.1 kg over the following year. Derived from adjacent rows of the same CDC table. |
| Spread between 3rd and 97th percentile | 21.0 kg | At this age the middle 94% of boys fall between 22.1 kg and 43.1 kg. Weight varies far more than height at the same age. |
| Share of the age-20 median reached | 40.6% | The 50th percentile here is 28.7 kg; the CDC table ends at age 20 with a 50th percentile of 70.6 kg. |
| Difference from girls at the same age | -0.5 kg | The 50th percentile for boys is 0.5 kg lighter than that for girls at this age. |
| Median height and resulting BMI | 133.7 cm · BMI 16.0 | Combining the 50th percentile of weight (28.7 kg) with the 50th percentile of stature (133.7 cm) from the CDC weight-for-age and stature-for-age tables. |
These are population reference statistics only. They describe how a group of children of this age and sex is distributed, and say nothing about any individual child.
How to read this table
For this table, a percentile is a position in the cited reference distribution for children of the same sex and completed age band. The 50th percentile is the median. These values are not a personal forecast, target, diagnosis, or recommendation.
Measurement: CDC reports weight for this completed-month age band.
Adjacent ages
Height predictor
This reference table does not embed the calculator. Open the homepage height predictor separately.
Data source
Dataset: CDC 2000 Growth Charts: weight-for-age, 2-20 years. All displayed kilograms values come from wtage.csv, row Sex=1, Agemos=108.5 (completed month 108 band). The pounds column is a direct unit conversion. See the official CDC dataset page.
Reference distribution only. This page does not provide medical advice, a diagnosis, or an individual forecast.