bmi / BMI
Child BMI calculator
The BMI figure first, then where it sits among children the same age.
Compared with peers
BMI
15.62kg/m²
- 126 cm
- Height (cm)
- 24.8 kg
- Weight (kg)
{percentileOrdinal} percentile World Health Organization
Weight in kilograms divided by height in metres squared. The placing comes from a BMI-for-age table.
Step by step
Two steps, kept in two blocks on the page. The first is pure arithmetic and needs only height and weight. The second needs age, sex and a standard, because the same 15.6 means quite different things at three and at thirteen. Height and weight alone still give you a complete answer — just the first one.
What this number cannot tell you
The adult cut-offs are not used. 18.5 / 25 / 30 were drawn for adults, and applied to a child they produce a confidently wrong conclusion: children’s BMI rises and falls with age by design, and bottoms out around two or three. A child’s BMI is only readable against other children the same age.
An example
126 cm and 24.8 kg gives a BMI of 15.62.
Common questions
- Why is there no number?
- There is no figure here that can be given with confidence, so none is given. The normal range for questions like this is wide anyway — a few minutes with a paediatrician or dentist usually settles it.
- What if my child’s age or country is not covered?
- It will say plainly that this age is not covered, rather than borrow figures from another age or another country. How far a standard reaches is set by whoever published it, and stretching it gives a placing that is simply wrong.
Next
The others in the same group.