Health / Measurements
Child BMI Percentile Calculator
Calculate CDC BMI-for-age percentile, weight category and percentage of the 95th percentile for ages 2–19.
Child BMI Percentile Calculator: Uses the CDC 2000 LMS parameters below P95 and the 2022 half-normal extension at and above P95. Looks up completed calendar months plus 0.5 without interpolation. The compact local table retains every sex, age, L, M, S and sigma value. Runs 100% locally in your browser with zero server file uploads.
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- Health & sport tools
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- Free · no sign-up
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- Ready to use
Runs entirely in your browser
For ages 2 through 19. Uses the US CDC 2000 reference and the 2022 extended method above the 95th percentile.
Enter both dates to calculate the age-specific result.
BMI is a screening measure, not a diagnosis. See a clinician to interpret growth, development and health together.
Age uses completed calendar months plus the table's 0.5 offset: 48.5 represents ages 48 to below 49 months. End-of-month birthdays use the month's last day. No interpolation is used. Height and weight should be measured without shoes or heavy clothing.
The percentile compares BMI with the reference population of the same age and sex. Below P95 the calculator uses LMS; from P95 it uses the CDC half-normal extension. Categories use unrounded BMI thresholds.
CDC 2000 and 2022 growth references
CDC extended BMI-for-age data and monthly-age convention: https://www.cdc.gov/growthcharts/extended-bmi-data-files.htm . CSV: https://www.cdc.gov/growthcharts/data/extended-bmi/bmi-age-2022.csv . US government public-domain work. Extended equation in CDC SAS program, page 3: https://stacks.cdc.gov/view/cdc/158532/cdc_158532_DS13.pdf . Accessed / DATA_CHECKED: 2026-10-04.
CDC BMI category definitions
Ages 2 through 19: underweight below P5; healthy P5 to below P85; overweight P85 to below P95; obesity at or above P95. CDC also describes class 2/3 thresholds and their BMI 35/40 alternatives: https://www.cdc.gov/bmi/child-teen-calculator/bmi-categories.html . Screening measure, not a diagnosis; see a clinician. Accessed / DATA_CHECKED: 2026-10-04.
How to use it
- Enter birth and measurement dates and the sex used by the CDC chart.
- Enter measured height and weight in cm/in and kg/lb.
- Read the percentile, BMI category and percentage of P95.
Privacy & limitations
Measurements stay in your browser. Nothing is uploaded.
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Frequently asked questions
What does the percentile mean?
It compares BMI with the US reference population of the same age and sex. It does not diagnose health.
How is high BMI handled?
The extended percentile is 90 + 10 × Phi((BMI − P95) / sigma). Class 2 and 3 thresholds also show 120% and 140% of P95, with the CDC-listed absolute BMI alternatives of 35 and 40.
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