Weight for boys at 13 years
At 13 years, the median weight for boys on the CDC 2000 growth charts is 45.6 kg (100 lb 8 oz): half of boys this age weigh less and half more. The middle half of boys, from the 25th to the 75th percentile, falls between 40.2 and 52.4 kg, a spread of 12.2 kg. The outer lines of the chart, the 3rd and 97th percentiles, sit at 32.8 and 70.0 kg.
Since 12 years, the median has risen by 5.12 kg over 1 year. By 14 years it reaches 51.0 kg.
For girls at 13 years the median is 45.8 kg, 0.23 kg more than for boys, which is why the charts are drawn separately by sex.
From 2 years CDC recommends its own 2000 growth charts, which draw the 3rd to the 97th percentile; under 2, the WHO charts draw the 2nd to the 98th.
Reading the table: a boy at 13 years who weighs 49.7 kg is at about the 66th percentile, meaning that out of 100 boys this age, about 66 weigh less.
Percentiles at 13 years
Download CSV (all ages)| Percentile | z-score | Metric | Imperial |
|---|---|---|---|
| 3rd | −1.88 | 32.81 kg | 72 lb 5 oz |
| 5th | −1.64 | 34.06 kg | 75 lb 1 oz |
| 10th | −1.28 | 36.15 kg | 79 lb 11 oz |
| 25th | −0.67 | 40.16 kg | 88 lb 9 oz |
| 50th (median) | 0.00 | 45.59 kg | 100 lb 8 oz |
| 75th | +0.67 | 52.41 kg | 115 lb 9 oz |
| 90th | +1.28 | 60.18 kg | 132 lb 11 oz |
| 95th | +1.64 | 65.82 kg | 145 lb 2 oz |
| 97th | +1.88 | 69.99 kg | 154 lb 5 oz |
CDC 2000 charts draw the 3rd to the 97th percentile. Values computed with the LMS method from the published tables (retrieved 2026-10-05).