CDC BMI-FOR-AGE · AGES 2–18
Child BMI percentile calculator
For children, the useful comparison is BMI-for-age: BMI placed on an age- and sex-specific CDC reference. The raw BMI number alone is not interpreted the same way as adult BMI.
Calculate child BMI percentile ↗WORKED EXAMPLE
32 kg, 138 cm, age 10
A 10-year-old boy weighing 32 kg and measuring 138 cm has a BMI of 16.8, about the 53.5th percentile in the CDC reference. Exact dates can move the result slightly.
How to measure
- Measure weight in light clothing on a level digital scale.
- Measure standing height without shoes, heels together, looking straight ahead.
- Use weight and height taken on the same date, then enter the exact birth and measurement dates.
BMI number versus BMI percentile
| Result | What it shows | What it does not show |
|---|---|---|
| Raw BMI | Weight divided by height squared. | Age- or sex-specific context. |
| BMI-for-age percentile | Position in the CDC reference for age and sex. | A diagnosis or complete health assessment. |
| Weight-for-age percentile | Weight compared at the same age and sex. | Body proportions or weight status. |
Calculation coverage
The site supports the second birthday through the 18th birthday. It calculates BMI from kilograms and metres, then uses interpolated CDC parameters for the child’s exact age.
Questions parents ask
Is child BMI interpreted like adult BMI?
No. A child’s BMI is compared with an age- and sex-specific CDC reference. An adult BMI category should not be applied to a child.
Why do age and sex matter?
Body proportions change throughout childhood, and the CDC reference curves differ by age and sex. Exact dates provide a more precise age for the comparison.
What does a BMI percentile diagnose?
Nothing by itself. It is a screening and reference comparison that needs measurement quality, growth history and clinical context.
What happens above the CDC 95th percentile?
The calculator uses the CDC 2022 extended BMI method for high values instead of extending the original CDC 2000 LMS curve beyond its intended upper range.
Sources: CDC 2000 BMI-for-age data · CDC extended BMI data · methodology.
Review status: Maintained by Baby Growth and technically reviewed on 29 September 2026. Calculations and product ranges are checked against the cited WHO, CDC and manufacturer sources. This independent tool has not received clinical review and does not replace professional care.