BMI Calculator
Check your Body Mass Index with metric units.
How to use the BMI calculator
Enter your height in centimetres and your weight in kilograms, then press Calculate BMI. You will see your Body Mass Index, the matching category and a healthy weight range for your height.
What BMI is
Body Mass Index is your weight in kilograms divided by the square of your height in metres. It was designed as a quick screening number to compare body weight across large groups of people. The World Health Organization uses these adult categories: below 18.5 is underweight, 18.5 to 24.9 is normal weight, 25 to 29.9 is overweight, and 30 or above is obesity.
What BMI does not tell you
BMI does not separate muscle from fat, so athletes and people with a lot of muscle can have a high BMI while being healthy. It also does not show where fat is stored on the body, which matters for health. Some health bodies suggest lower cut-off points for people of South Asian origin, because health risks can begin at a lower BMI. For these reasons BMI is a starting point for a conversation, not a diagnosis.
This calculator is meant for adults aged 18 and over. Children and teenagers are assessed using age- and sex-specific growth charts instead.
Important
This tool provides general information only and is not medical advice. Please speak to a doctor or qualified health professional before making decisions about your diet, exercise or health. See our disclaimer for more details.
Frequently asked questions
Is BMI accurate for everyone?
No. It is a simple screening measure. It can overestimate body fat in muscular people and underestimate it in older adults who have lost muscle.
Can I use this calculator for children?
No. Children’s BMI must be compared against growth charts for their age and sex. Please ask a paediatrician.
Do you store my height and weight?
No. The calculation happens in your browser and nothing is saved.