Child BMI Percentile Calculator – Growth & Weight Assessment for Kids

The BMI percentile is an age- and sex-specific measure used for children and teens (aged 2-20) to assess their growth. Unlike adult BMI, which uses fixed categories, a child's BMI is plotted on a growth chart, and the resulting percentile indicates where their BMI ranks compared to children of the same age and gender in a reference population. For example, a 75th percentile means that 75% of children of the same age and gender have a lower BMI.

The standard categories are based on the BMI percentile: **Underweight** (Below 5th percentile), **Healthy Weight** (5th percentile to less than 85th percentile), **Overweight** (85th percentile to less than 95th percentile), and **Obesity** (95th percentile or greater). These categories are essential for pediatricians to identify potential health risks.

The BMI formula itself (weight/height²) is the same, but the **interpretation** is different. An adult BMI uses static thresholds. For children, the healthy range changes dramatically with age and varies between genders due to natural growth spurts and changing body composition. Therefore, the result must be compared to a **growth chart** to get the age- and sex-specific percentile.

The **CDC (Centers for Disease Control and Prevention)** charts are generally used for children aged 2 and older in the United States and reflect growth patterns of U.S. children. The **WHO (World Health Organization)** charts are often recommended for all children up to age five, as they represent how children *should* grow under optimal conditions globally, but can be used up to age 19. For children aged 2-5, the WHO charts may be preferred.

A single measurement is a snapshot. The most important step is to **consult your child’s pediatrician**. They can perform a comprehensive evaluation, including diet, physical activity, family history, and other health screenings. The pediatrician can provide personalized advice or recommend a specialist like a registered dietitian. Do not put your child on a diet without medical supervision.