Child BMI Calculator
BMI and category for children.
Enter your values
ⓘ Live results
Results
- BMI
- 16.8
- Category (approximate)
- Healthy weight
- Typical BMI for age
- 18.7
- Difference from typical
- -1.9
- Healthy weight range
- 31.8–40.4 kg
Quick answer
Children's BMI is interpreted against age and sex percentiles, not the fixed adult cut-offs.
BMI = kg ÷ m²
How to use the Child BMI Calculator
- 1Enter the child's weight in kilograms.
- 2Enter height in centimetres.
- 3Enter their age in years.
Worked example
Using the values the calculator loads with:
Inputs
- Weight32 kg
- Height138 cm
- Age10 years
Results
- BMI16.8
- Category (approximate)Healthy weight
- Typical BMI for age18.7
- Difference from typical-1.9
- Healthy weight range31.8–40.4 kg
Frequently asked questions
Why can't I use adult BMI?
Children's body composition changes with age, so cut-offs shift each year.
Is BMI accurate for athletic kids?
It can overstate fat in muscular children — use it alongside other measures.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.