Kids BMI Calculator
Calculate BMI percentile for children ages 2-19 using CDC growth charts. Get accurate BMI-for-age assessment.
Your Child's BMI
When to Use This Kids BMI Calculator
Our free kids BMI calculator helps parents and healthcare providers monitor children's growth.
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Pediatric Well-Visits
Prepare for your child's annual check-up with accurate BMI percentile data to discuss with your pediatrician.
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Growth Monitoring
Track your child's BMI percentile over time to ensure they maintain a healthy growth trajectory.
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School Health Programs
Support school health screenings and fitness assessments with accurate BMI-for-age calculations.
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Sports Physicals
Athletes and parents can monitor body composition as part of youth sports participation requirements.
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Nutritional Planning
Work with dietitians or nutritionists using accurate BMI data to develop healthy eating plans for children.
Frequently Asked Questions
- Why use percentiles instead of BMI categories for children?
- Children's bodies change significantly as they grow. A BMI that's normal for a teenager would be concerning for a toddler. Percentiles account for age and sex differences in healthy body composition.
- What is the CDC LMS method?
- The CDC LMS method uses three parameters (Lambda, Mu, Sigma) to calculate precise percentiles based on growth chart data from thousands of children. It's the gold standard for pediatric BMI assessment.
- Is this calculator accurate for all children?
- This calculator uses CDC growth charts developed primarily from US children's data. Results may vary for children from different ethnic backgrounds. Always consult your pediatrician for personalized assessment.
- What should I do if my child's BMI is outside the healthy range?
- Don't panic - BMI is just one measure of health. Schedule an appointment with your pediatrician to discuss your child's overall health, diet, and activity level for personalized guidance.
- Can I use this for children under 2 years old?
- No, this calculator is designed for ages 2-19. For infants and toddlers under 2, weight-for-length charts are used instead. Consult your pediatrician for appropriate growth assessment.
Kids BMI Calculator Help
How to Use
- Choose your preferred unit system (Metric or Imperial)
- Enter your child's height and weight
- Select your child's age in years and months
- Select whether your child is a boy or girl
- Click 'Calculate BMI' to see the results
Understanding BMI Percentiles for Children
Unlike adult BMI, children's BMI is expressed as a percentile that compares your child to other children of the same age and sex.
- Underweight (<5%): Below 5th percentile
- Healthy Weight (5-84%): 5th to 84th percentile
- Overweight (85-94%): 85th to 94th percentile
- Obesity (≥95%): 95th percentile and above
Important Tips
- BMI percentile is a screening tool and should be interpreted by a healthcare provider.
- Results do not account for muscle mass, bone structure, or pubertal stage.
- For children under 2 years, consult your pediatrician for appropriate growth assessment.