BMI Calculator for Kids & Teens
For ages 2 to 19. See your child’s BMI-for-age percentile on the CDC growth charts and what it means.
Ages 2–19 · Based on CDC growth charts · Updated
Enter your child’s details
BMI-for-age percentile
BMI –
Percentiles compare your child with children of the same age and sex.
A single result is a snapshot. Children’s BMI changes as they grow, so their doctor looks at it over time.
How BMI-for-age percentiles work
Body fat changes a lot as children grow, and differs between girls and boys. So a child’s BMI is compared with children of the same age and sex on the CDC growth charts, and the result is a percentile. A child at the 60th percentile has a higher BMI than 60% of children of the same age and sex in the reference data.
BMI categories for children and teens
| BMI-for-age percentile | Category |
|---|---|
| Below the 5th | Underweight |
| 5th to below the 85th | Healthy weight |
| 85th to below the 95th | Overweight |
| 95th or above | Obesity |
| Well above the 95th | Severe obesity |
“Well above the 95th” means a BMI at least 20% higher than the BMI at the 95th percentile for the child’s age and sex. If that BMI is 20, for example, it starts at 24. CDC calls this severe obesity.
Why adult categories don’t apply
The same BMI means different things at different ages. A BMI of 19 is above the 95th percentile for a 6-year-old boy, but below the median for a 17-year-old boy (about 21). That’s why the adult cut-offs, such as 25 for overweight, are only used from age 20.
The 2022 extended charts
In 2022, CDC released extended BMI-for-age charts that describe very high BMIs more accurately. Above the 95th percentile, this calculator uses the extended method; below it, the original 2000 charts, which are unchanged.
Measuring your child
- Measure height without shoes, with your child standing straight against a wall, heels together.
- Weigh in light clothing, on the same scale each time if you’re tracking over time.
- Use the exact age in years and months: percentiles change month by month.
When to talk to a doctor
If the result is outside the healthy range, or you’re worried about your child’s growth or eating, talk to their pediatrician, who can look at growth over time and at their overall health. Don’t put a child on a weight-loss diet without medical advice.
If you’re worried about your child’s eating, free and confidential support is available from ANAD.
For adults 20 and older, use the adult BMI calculator.