I'm 13. My BMI said I'm overweight, but I'm very athletic and not at all fat. It's kind of depressing to be told I'm overweight when I don't think I am.
- Stephanie*

Body mass index (also known as BMI) is just one of the ways to estimate how much body fat a person has. BMI can be useful — but it's not perfect.

For kids and teens, it can be tricky to tell what a BMI reading means. That's because kids' weights and amounts of body fat can change quickly as they go through puberty. Sometimes athletic kids who build muscle with exercise can have BMI measurements that say "overweight" when they don't have too much body fat at all.

The best thing you can do is talk with your doctor or school nurse for help interpreting what your BMI number means. There's a good chance you'll find out that you're fine!

Reviewed by: Mary L. Gavin, MD
Date reviewed: January 2013

Although we can't reply personally, you may see your question posted to this page in the future. If you're looking for medical advice, a diagnosis, or treatment, consult your doctor or other qualified medical professional. If this is an emergency, contact emergency services in your area.

*Names have been changed to protect user privacy.