BMI Percentile Calculator for Children & Teens

How It Works

This tool takes a child or teen's age, gender, height, and weight, calculates BMI, then interpolates a percentile against reference curves modeled on CDC growth chart data for the 5th, 50th, 85th, and 95th percentile bands. Ages between whole years (e.g. 8.5) are interpolated between the nearest reference ages, so results stay smooth across the full 2–20 year range instead of jumping between fixed brackets.

How to Use This Tool

1. Enter Age: Type the age in years (2 to 20; decimals like 8.5 are accepted).
2. Select Gender: Choose either Male or Female.
3. Enter Height: Type height in centimeters (50–220).
4. Enter Weight: Type weight in kilograms (2–200).
5. Click the Button: Press "Calculate BMI Percentile" for your result.

Worked Example

A 10-year-old boy who is 140 cm tall and weighs 34 kg has a BMI of 34 ÷ 1.40² = 34 ÷ 1.96 ≈ 17.3. This calculator's reference curve for 10-year-old boys places the 50th percentile at a BMI of 16.6 and the 85th at 19.8, so a BMI of 17.3 lands around the 58th percentile — a healthy weight for his age.

What the Output Means

The result box shows BMI in kg/m², a percentile ranking, and a weight status category: Underweight, Healthy Weight, Overweight, or Obese. A chart below the result plots the 5th, 50th, 85th, and 95th percentile curves across ages, with a red dot marking the child's own BMI.

Limitations and Special Notes

This calculator's percentile curves are modeled on CDC growth chart data but are a simplified interpolation, not the full clinical dataset, so treat results as a close estimate. It is a quick screening tool, not a diagnosis — for a comprehensive view of a child's growth, ask a doctor.

Common Use Cases

• Parents checking a child's growth between well-child visits.
• A quick reference before discussing weight trends with a pediatrician.
• Schools or camps doing general health screening.