BMI Calculator
Work out body mass index from height and weight in metric or imperial units.
Enter your values
Fill in every field marked as required, then choose Calculate.
Result
Results appear below the form and can be copied or downloaded.
How it works
Method
BMI = weight in kilograms divided by the square of height in metres. Imperial values are converted first (1 lb = 0.45359237 kg, 1 in = 2.54 cm). Categories follow the World Health Organization adult ranges: under 18.5 underweight, 18.5 to 24.9 healthy weight, 25 to 29.9 overweight, 30 and above obesity.
Units
Metric: kilograms and centimetres. Imperial: pounds and inches. BMI itself is expressed in kg/m².
Examples
- 70 kg and 175 cm gives a BMI of 22.9 (healthy weight).
- 180 lb and 70 in gives a BMI of 25.8 (overweight).
Limitations
BMI is a screening measure for adults. It does not distinguish muscle from fat and is not a diagnosis. It is not suitable for children, pregnancy or athletes with high muscle mass.
Frequently asked questions
How is the result calculated?
BMI = weight in kilograms divided by the square of height in metres. Imperial values are converted first (1 lb = 0.45359237 kg, 1 in = 2.54 cm). Categories follow the World Health Organization adult ranges: under 18.5 underweight, 18.5 to 24.9 healthy weight, 25 to 29.9 overweight, 30 and above obesity.
Are there any limitations?
BMI is a screening measure for adults. It does not distinguish muscle from fat and is not a diagnosis. It is not suitable for children, pregnancy or athletes with high muscle mass.