How this calculator works
Body mass index (BMI) is weight in kilograms divided by height in meters squared. It is a screening measure, not a diagnosis. It does not directly measure body fat or account for muscle mass, pregnancy, or individual health.
The formula
BMI = Weight (kg) ÷ Height (m)²A quick example
At 70 kg and 175 cm (1.75 m), BMI = 70 ÷ 1.75² = 22.86, within the common adult healthy-weight reference range.
How to use this calculator
- Enter your weight in kilograms.
- Select centimeters or meters and enter your height.
- Calculate and read the result with its limitations in mind.
Metric and imperial measurements
Choose Metric for kg with cm or m, or Imperial for lb, feet and additional inches. Imperial measurements are converted using 1 lb = 0.45359237 kg and 1 in = 0.0254 m before applying the same BMI formula. Adult BMI is a screening reference, not a diagnosis.
A few common questions
What are the common adult BMI ranges?
Below 18.5: underweight; 18.5 to less than 25: healthy weight; 25 to less than 30: overweight; 30 and above: obesity. Categories use the unrounded result.
Is this suitable for children?
No. Children and teenagers need age- and sex-specific assessment. This tool is for adults aged 20 and over.
Can BMI diagnose a health condition?
No. BMI is only one screening measure. A qualified health professional can interpret it alongside your medical history and other measurements.
Reference: CDC: Adult BMI categories