Body Mass Index (BMI)

Online calculator for calculating the Body Mass Index (BMI) for children, adolescents and adults

The calculator calculates the BMI and arranges the results accordingly to age and gender according to the BMI tables for children, adolescents and adults and displays the result graphically.


BMI progress for children, teenager and adults

The diagram shows the progression of BMI areas for children, adolescents and adults. The star in the diagram shows the actual calculated BMI value.

BMI Calculation

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 ÷ L2

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

Example for the calculation of the BMI:

For example, if a person is 175 cm tall and weights 65 kg, then the BMI is calculated as follows:

BMI = m ÷ L2 = 65 ÷ 1.752 = 65 ÷ (1.75 ⋅ 1.75) = 65 ÷ 3.0625 = 21.2

The interpretation of the calculated BMI value is based on the comparison with the tabulated average values of the population. That is, the normal range (green in the diagrams) corresponds to the average in the population at the time of the survey.

Explanation of the BMI

The Body Mass Index (BMI) is a measure for the assessment of the body weight of a person in relation to its body size.

The BMI is only a rough guideline as it does not take into account the stature and sex or the individual composition of the body mass from fat and muscle tissue of a human being.

Age and gender play an important role in the interpretation of BMI. Men generally have a higher proportion of muscle mass in total body mass than women. The BMI can also be used in children and small children as a measure for the healthy development of the child. However, the BMI is interpreted by adults according to the same formula as the BMI for childs but is interpreted according to age.

The limits of an appropriate BMI are strongly related to the development of the child. For example, the rapid growth of the length in the initial phase of puberty and the like is depicted. If a child develops these developmental phases sooner or later than the average, a BMI that is too high or too low, depending on the age group, can be present.

References: Body mass index at Wikipedia Body shape index at Wikipedia

Body Mass Calculators

BMI for age: Infants 0 to 1 year 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