Is BMI Useful for Children?
Published April 2, 2025 • CalcFat Blog
While BMI is a helpful indicator for adults, its use for children is a bit more complex. For kids, BMI is interpreted using percentiles based on age and gender.
How Is BMI Calculated for Children?
The basic formula is the same: weight (kg) divided by height (m²). However, instead of comparing the result to a fixed scale, it's plotted on a BMI-for-age growth chart created by the CDC or WHO.
What Are BMI Percentiles?
Percentiles rank a child's BMI in comparison to others of the same age and sex:
- Underweight: Below the 5th percentile
- Healthy weight: 5th to 85th percentile
- Overweight: 85th to 95th percentile
- Obese: Above the 95th percentile
Limitations of BMI for Kids
Just like with adults, BMI doesn’t measure fat directly. Children grow at different rates and their body composition varies, so other indicators like diet, activity level, and family history are also important.
Why It Still Matters
BMI can be a useful screening tool to detect potential weight-related health issues early. Doctors often use it alongside other data to track long-term development and prevent chronic conditions.
Talk to your pediatrician if you’re concerned about your child’s BMI or growth curve. Professional guidance is key to interpreting the numbers correctly.