A “normal” weight for a 12‑year‑old girl is a range, not a single number, and it depends a lot on height, body build, and stage of puberty. Growth charts that doctors use show that many healthy 12‑year‑old girls fall somewhere between about 68 and 135 pounds (around 31 to 61 kg).

Typical ranges

Most medical sources using CDC growth charts describe these points for 12‑year‑old girls:

• Common healthy range: roughly 68–125/135 lb (about 31–61 kg), covering the 5th–85th or 5th–95th percentiles.

• Middle (50th percentile, “average”): about 90–92 lb (around 41–42 kg).

Being below or above these numbers does not automatically mean a problem, because some girls are naturally smaller or larger, especially around puberty.

Why height and puberty matter

The same weight can be healthy for a taller girl but high for a shorter girl, so doctors look at weight together with height using BMI‑for‑age percentiles. Puberty can also change weight quickly as girls gain height and normal body fat, so a girl who was light one year might be much heavier the next while still being healthy.

If there is any worry about being underweight, overweight, or growing too fast or too slowly, the safest next step is to talk with a pediatrician or nurse, who can plot height and weight on a growth chart and look at overall health, nutrition, and activity.