Child BMI Percentile Calculator

Child BMI Percentile is evaluated from Child's Sex, Age and Weight. The calculation reports BMI, Weight Category and Approximate Percentile.

Results

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About the Child BMI Percentile Calculator

Child BMI Percentile is treated here as a quantitative relation between Child's Sex, Age, Weight and Height and BMI, Weight Category and Approximate Percentile.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
BMI = Weight (kg) / Height^2 (m^2)
Weight category is assigned based on approximate BMI-for-age percentile thresholds (simplified from CDC tables). For precise clinical percentiles, consult CDC BMI-for-age growth charts.

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

BMI = Weight (kg) / Height^2 (m^2)
Weight category is assigned based on approximate BMI-for-age percentile thresholds (simplified from CDC tables). For precise clinical percentiles, consult CDC BMI-for-age growth charts.

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: 10-Year-Old Boy — Average Weight

Inputs

sex: male age_years: 10 weight_kg: 32 height_cm: 140

BMI: 16.3 kg/m^2. Weight Category: Healthy Weight (5th-85th percentile). Approximate Percentile: 5th-84th percentile

With Child's Sex = male, Age = 10, Weight = 32 and Height = 140 as the stated inputs, the result is BMI = 16.3 kg/m^2, Weight Category = Healthy Weight (5th-85th percentile) and Approximate Percentile = 5th-84th percentile. Each value corresponds to the declared output fields.

Example 2: 8-Year-Old Girl — Overweight Range

Inputs

sex: female age_years: 8 weight_kg: 30 height_cm: 120

BMI: 20.8 kg/m^2. Weight Category: Overweight (85th-95th percentile). Approximate Percentile: 85th-94th percentile

With Child's Sex = female, Age = 8, Weight = 30 and Height = 120 as the stated inputs, the result is BMI = 20.8 kg/m^2, Weight Category = Overweight (85th-95th percentile) and Approximate Percentile = 85th-94th percentile. Each value corresponds to the declared output fields.

Example 3: Teenage Boy — Healthy Athlete

Inputs

sex: male age_years: 16 weight_kg: 68 height_cm: 178

BMI: 21.5 kg/m^2. Weight Category: Obese (>= 95th percentile). Approximate Percentile: >= 95th percentile

With Child's Sex = male, Age = 16, Weight = 68 and Height = 178 as the stated inputs, the result is BMI = 21.5 kg/m^2, Weight Category = Obese (>= 95th percentile) and Approximate Percentile = >= 95th percentile. Each value corresponds to the declared output fields.

Example 4: Young Child — Underweight Concern

Inputs

sex: female age_years: 4 weight_kg: 13 height_cm: 100

BMI: 13 kg/m^2. Weight Category: Underweight (< 5th percentile). Approximate Percentile: < 5th percentile

With Child's Sex = female, Age = 4, Weight = 13 and Height = 100 as the stated inputs, the result is BMI = 13 kg/m^2, Weight Category = Underweight (< 5th percentile) and Approximate Percentile = < 5th percentile. Each value corresponds to the declared output fields.

Common Use Cases

Calculate BMI percentile for children aged 2–19
Determine if a child's weight is healthy for their age and sex
Track a child's weight status over time
Understand CDC BMI-for-age weight categories