Is this the same as the CDC BMI calculator for children?

It uses the same CDC 2000 BMI-for-age growth chart data (the LMS tables behind the CDC Child and Teen BMI Calculator) to turn your child's BMI, age in months and sex into a percentile. For children at or above the 95th percentile, the CDC now also uses extended charts to describe severe obesity, so ask your pediatrician about readings in that range.

What is a healthy BMI for a child?

A healthy BMI for children is determined by age and sex percentiles, not fixed numbers like adults. Children between the 5th and 85th percentile are considered healthy weight. Below the 5th percentile is underweight, 85th-95th percentile is overweight, and above the 95th percentile is considered obese. These percentiles account for normal growth variations at different ages.

How is child BMI different from adult BMI?

Child BMI uses the same formula (weight/height²) but is interpreted differently. For adults, fixed BMI ranges apply to everyone. For children ages 2 to 19, BMI is compared to growth charts based on age and sex because body composition changes significantly during development. A BMI of 18 might be healthy for a 7-year-old but underweight for a 16-year-old.

At what age can you calculate a child's BMI?

The CDC BMI-for-age growth charts cover children and teens from age 2 through 19. For infants and toddlers under 2, healthcare providers use weight-for-length charts instead of BMI. From age 20, adult BMI categories apply. Our calculator uses the CDC BMI-for-age data for ages 2 through 19.

Can a muscular child have a high BMI but still be healthy?

Yes, BMI doesn't distinguish between muscle and fat mass. Athletic or muscular children may have higher BMIs while being perfectly healthy. This is why BMI should be interpreted alongside other factors like waist circumference, physical activity, diet quality, and clinical assessment by a healthcare provider.

What should I do if my child's BMI is outside the healthy range?

First, consult your pediatrician - they can assess whether there's a genuine concern and rule out medical causes. For overweight children, focus on healthy lifestyle changes for the whole family: more physical activity, better food choices, and limited screen time. Avoid restrictive dieting in children as it can harm growth. For underweight children, your doctor may recommend nutrition counseling.

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Pediatric BMI Calculator (CDC Percentiles)

Q: How often should I check my child's BMI?

Pediatricians typically check BMI at annual well-child visits, which is sufficient for most children. More frequent monitoring may be recommended if there are concerns about weight. Remember that BMI is just one health indicator - growth patterns, activity levels, and eating habits are equally important. Don't obsess over single measurements.

Short answer: for children and teens ages 2 to 19, BMI is judged by percentile for age and sex on the CDC growth charts, not adult cutoffs: under the 5th percentile is underweight, 5th to under 85th is a healthy weight, 85th to under 95th is overweight, and 95th or above is obesity. Enter age, sex, height and weight below to get the percentile.

Updated 2026. Uses CDC 2000 BMI-for-age growth chart data.

Calculate Your Child's BMI

Get personalized health recommendations by age

Age (years and months)

Sex

Height

Weight

2-5 years

4-5 lbs/year

2-3 in/year

6-11 years

5-7 lbs/year

2-2.5 in/year

12-17 years

Variable

Puberty growth spurt

Common Questions

What is a healthy BMI for kids?

Is my child overweight or just going through a growth phase?

How often should I check my child's BMI?

My athletic child has a high BMI. Should I be concerned?

What's the difference between BMI percentile and BMI number?

Should I put my overweight child on a diet?

Medical Disclaimer

This calculator provides educational estimates only and is not a substitute for professional medical advice. Always consult your pediatrician or healthcare provider for guidance specific to your child.

Last reviewed: December 2024|

Sources:CDC BMI Calculator AAP Healthy Weight