The BMI calculator calculates the BMI and ranks the result according to age and sex according to the BMI tables to a week for infants and displays the result graphically.

The BMI for babies and toddlers is classified according to the average values determined by the WHO. The weight entered is classified according to age and gender into deviation ranges from the mean value (median). A distinction is made between three deviation ranges: σ, 2σ and 3σ. The following applies to the ranges:

- In the ±σ range, 68.27% of all children in this age group are
- In the ±2σ range, 95.45% of all children in this age group are
- In the ±3σ range, 99.73% of all children in this age group are

In the following, the σ range is referred to as normal weight. The range σ to +2σ with overweight and above +2σ with severely overweight (obesity). Similarly in the lower range for underweight and severely underweight.

Weight

kg

Gender

Height

cm

Age

Units

The diagram shows the BMI value in the age-dependent diagram with the colored classification areas. The diagram shows the course of the BMI limits for the first weeks of the baby's life. The diagram is created gender dependent for boys and girls.

The values for the BMI in the range of the entered data and for the corresponding gender are listed here.

The Body Mass Index (BMI) is a measure that sets the weight in the ratio to the square of the body weights. The BMI is a rough guide, since it does not take into account either stature or weight distribution. Since the beginning of the 1980s, the BMI has also been used by the World Health Organization. The present BMI classification of the WHO has essentially existed since 1995.

BMI = m ÷ L^{2}

with m : Weight in kg, L : Height in m

For example, if a baby is 60 cm tall at the age of 3 months and weighs 6 kg, the BMI is calculated as follows:

BMI = m ÷ L^{2} = 6 ÷ 0.6^{2} = 6 ÷ (0.6 ⋅ 0.6) = 6 ÷ 0.36 = 16.67

The calculated BMI value is interpreted by comparing it with the tabulated average values of the population. This means that the normal range (green in the diagrams) corresponds to the average in the population at the time of the survey. For a boy of this age, the normal range is between 15.5 and 18.4 and for a girl between 14.9 and 17.9. In this example, the BMI is therefore within the normal range for both a boy and a girl.

The Body Mass Index (BMI) is a measure of a person's body weight in relation to their height. The BMI is only a rough guide value, as it does not take into account a person's stature or the individual composition of body mass from fat and muscle tissue. Age and gender play an important role in the interpretation of the BMI. In children and infants, the BMI can be used as a rough guideline for the healthy development of the child. The BMI is calculated using the same formula as the BMI of adults, but is interpreted according to age. The limits of an appropriate BMI are strongly related to the child's developmental stage. If a child goes through a developmental phase sooner or later than average, a BMI that is too high or too low according to the age group may be present despite normal weight.

- The easiest way to determine the height of children is to stand with their backs against a wall or door frame.
- Both the heels and the back of the head rest against the wall.
- A right-angled tool (e.g. large set square or book) is placed on the wall and pushed down until it touches the head. This can be used to make an accurate size mark on the wall.
- The distance from the ground to the mark gives the body height.

- Children under two years of age are best measured lying down.
- It is helpful to have a second person available for support.
- The child lies flat on its back, legs extended and head resting. The feet point upwards at right angles.
- A tape measure is now used to measure from the bottom of the heel to the head.

**References: **Body mass index at Wikipedia
Body shape index at Wikipedia
World Health Organization WHO-Tables

**Baby and child: **
Baby and child weight
Baby and child body size
Weight to size of babies and children

**Body Mass Calculators**

BMI for age: Child and adults Childs 1 to 5 years

BMI progress charts: BMI Charts

Body mass indices: Calculation of the Body Indices

Body Mass Tables: BMI Tables BMI Index