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Pediatric BMI Calculator

Calculate a de-identified pediatric BMI and exact single-month-age percentile from the official CDC 2022 Extended BMI-for-Age parameters.

Use this result well

Inputs that matter
One de-identified source record containing the responsible CDC chart-sex selection, completed years, additional whole months and same-session standing height and weight
Output to expect
BMI, the exact sex- and single-month-age CDC percentile, the source P95 BMI, percent of P95 and the corresponding CDC screening range
How it works
Calculate metric BMI, select the bundled CDC 2022 Extended BMI-for-Age source row, use LMS through P95 and the CDC extended sigma method above P95; no annual-median approximation or age what-if is used
  • Verify identity, exact age, chart selection and calibrated same-session standing-height and weight measurements; rounding or a different measurement date can change the percentile.
  • Treat BMI as a screening indicator, not direct body-fat measurement or diagnosis; qualified pediatric review owns longitudinal growth, history, examination and any follow-up or treatment decision.

Choose your path

Built around the job you need to finish

Reproduce a de-identified pediatric BMI-for-age screening record with the exact CDC sex- and single-month-age parameters instead of an invented percentile estimate.

Pediatric clinician reconciling a growth record

Preserve exact month age, chart selection and same-session measurements while distinguishing screening from diagnosis.

Name the de-identified clinical record, copy completed years and months, the responsible chart selection, kilograms and standing centimeters.

Can compare BMI, percentile, P95 and percent-of-P95 to the reviewed record without an approximate annual lookup or treatment conclusion.

Caregiver reviewing measured values

Understand why the result depends on exact age and the sex-specific reference without entering identifying dates or a child name.

Use a de-identified home-measurement source and copy only the reviewed whole-month age and same-session values.

Sees transparent arithmetic, source boundaries and a prompt for qualified longitudinal review rather than diet or diagnosis advice.

Clinical educator testing extended BMI math

Verify LMS behavior below P95 and the CDC sigma method above P95 against official worked parameters.

Run male and female single-month examples on both sides of P95 and inspect the source row and steps.

Can trace official P95 and extended-percentile results and confirm the old annual-median ratio, sliders and proportional chart are absent.

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Reference & details

How it works

Reviewed metric BMI

CDC uses the same metric BMI equation for children and adults, but accurate same-session standing height and weight are essential. This tool copies the values from one named record and cannot validate technique or calibration.

BMI = weight (kg) ÷ height (m)²

Sex and single-month CDC source row

The bundled CDC 2022 Extended BMI-for-Age data retains full source precision for L, M, S, sigma and P95. A 120-month record uses the 120.5-month CDC row representing that month.

Row = CDC chart sex + (completed years × 12 + additional months)

Standard and extended percentile

CDC specifies a different extended method above P95. The result also reports percent of P95 and the screening range, while clinical interpretation remains with a qualified pediatric professional.

BMI ≤ P95: CDC LMS; BMI > P95: 90 + 10 × Φ((BMI − P95) ÷ sigma)

Updated: August 2026

Example Scenarios

A de-identified 10-year-0-month male-reference exercise with 35 kg and 140 cm produces BMI 17.86 and uses the exact 120.5-month CDC row—not a rounded annual median.

A reviewed 9-year-6-month record selects the 114.5-month female CDC row. Changing the month or rounding measurements may change the percentile, so preserve the source values.

When BMI exceeds the source P95 value, the calculator uses CDC's extended sigma equation and reports percent of P95. The output is still screening information, not a diagnosis or treatment direction.

FAQ

No annual-median ratio is used. The calculation selects the official CDC 2022 Extended BMI-for-Age row by chart sex and single month, preserves source precision, and follows CDC's separate equations through and above P95.

CDC data are indexed by single month of age. Whole years alone can select the wrong source row. The accepted range is 2 years 0 months through 19 years 11 months.

CDC BMI-for-age references are sex-specific. Copy the chart selection from the responsible clinician or reviewed record; this calculator does not decide which reference applies.

No. CDC describes BMI as a screening indicator and not a direct body-fat measure. Longitudinal growth, history, examination and follow-up require qualified pediatric review.

Do not enter identifying information. Use a de-identified record label and copy only completed years, additional months, chart selection and same-session measurements from the reviewed source.

About Pediatric BMI Calculator

Reproduce one reviewed pediatric BMI-for-age screening record without the old annual-median approximation. Name a de-identified source, copy the responsible CDC chart-sex selection, completed years plus months, and same-session metric measurements. The tool uses the official CDC LMS method through P95 and extended sigma method above P95; it does not verify identity or measurements, diagnose a condition, or recommend treatment.