The Body Mass Index (BMI) calculator computes one's body mass index using their weight and height.
INSTRUCTIONS: Choose units and enter the following:
BMI: The calculator returns the Body Mass Index (BMI).
Related Calculators:
The body mass index (BMI), or Quetelet index, is a measure of relative size based on the mass and height of an individual. The formula for BMI is as follows:
BMI = height / weight2
where:
The calculator makes the unit conversions and then computes the index in kilograms and meters. It also rounds to the nearest tenth.
Wikipedia (wikipedia.org/wiki/Boddy_mass_index) list the following interpretations for BMI.
General Interpretation:
| Category | BMI (kg/m2) | BMI Prime | ||
|---|---|---|---|---|
| from | to | from | to | |
| Very severely underweight | 15 | 0.60 | ||
| Severely underweight | 15 | 16 | 0.60 | 0.64 |
| Underweight | 16 | 18.5 | 0.64 | 0.74 |
| Normal (healthy weight) | 18.5 | 25 | 0.74 | 1.0 |
| Overweight | 25 | 30 | 1.0 | 1.2 |
| Obese Class I (Moderately obese) | 30 | 35 | 1.2 | 1.4 |
| Obese Class II (Severely obese) | 35 | 40 | 1.4 | 1.6 |
| Obese Class III (Very severely obese) | 40 | 1.6 | ||
International Interpretations:
The Hospital Authority of Hong Kong recommends the use of the following BMI ranges:[17]
| Category | BMI (kg/m2) | |
|---|---|---|
| from | to | |
| Underweight | 18.5 | |
| Normal Range | 18.5 | 23 |
| Overweight—At Risk | 23 | 25 |
| Overweight—Moderately Obese | 25 | 30 |
| Overweight—Severely Obese | 30 | |
Japan Society for the Study of Obesity (2000):[18]
| Category | BMI (kg/m2) | |
|---|---|---|
| from | to | |
| Low | 18.5 | |
| Normal | 18.5 | 25 |
| Obese (Level 1) | 25 | 30 |
| Obese (Level 2) | 30 | 35 |
| Obese (Level 3) | 35 | 40 |
| Obese (Level 4) | 40 | |
Sinagpore
| Health Risk | BMI (kg/m2) | |
|---|---|---|
| Risk of developing problems such as nutritional deficiency and osteoporosis | under 18.5 | |
| Low Risk (healthy range) | 18.5 to 23 | |
| Moderate risk of developing heart disease, high blood pressure, stroke, diabetes | 23 to 27.5 | |
| High risk of developing heart disease, high blood pressure, stroke, diabetes | over 27.5 | |
The index was devised by Adolphe Quetelet during the course of developing what he called "social physics", between 1830 and 1850.[1] The BMI for a person is defined as their body mass divided by the square of their height—with the value universally being given in units of kg/m2; however, vCalc allows the user to use other units via the pull-down menu.