BMI Percentile Calculator for Kids (CDC)
This BMI percentile calculator finds a child or teen's BMI-for-age percentile, the measure US pediatricians use for ages 2 through 19. Enter the age in years and months, sex, height in feet and inches and weight in pounds, and it computes BMI, then compares it with CDC growth chart data for the same age and sex using the CDC LMS method. You get the percentile, the z-score and the weight category: underweight, healthy weight, overweight or obesity. Adult BMI cut-offs do not apply to children, which is why percentiles are used. The data is built in, so nothing is uploaded.
BMI Percentile Calculator
BMI-for-age percentile for ages 2 to 20 from CDC growth chart data.
How to use the BMI Percentile Calculator
- Enter the child's age in years and months.
- Choose sex.
- Enter height in feet and inches and weight in pounds.
- Read the BMI, percentile and weight category.
CDC LMS method
BMI = 703 × lb ÷ in². z = ((BMI ÷ M)^L - 1) ÷ (L × S), using the L, M and S values for the child's age and sex; the percentile is the normal distribution area below z.
Features
- CDC BMI-for-age growth chart data
- Ages 2 to 20
- Percentile and z-score
- Weight category
- US units (lb, ft and in)
- Private, data built in
Frequently asked questions
What is a BMI percentile?
It shows how a child's BMI compares with US children of the same age and sex. The 60th percentile means a higher BMI than 60% of peers.
What BMI percentile is healthy?
The CDC defines underweight as below the 5th percentile, healthy weight as the 5th to below the 85th, overweight as the 85th to below the 95th, and obesity as the 95th or above.
Why don't adult BMI categories apply to kids?
Body fat changes a lot with age and differs between boys and girls, so the same BMI number means different things at 6 and at 16.
Where does the data come from?
From the CDC 2000 BMI-for-age growth chart LMS tables, sampled every 6 months and smoothly interpolated in between.
Is this accurate above the 97th percentile?
The CDC now uses extended charts for very high BMI. Above the 97th percentile this tool shows "above 97th" rather than an exact value.