Health and fitness tools
BMI Calculator
Calculate body mass index (BMI) from height and weight locally in your browser.
Calculate a BMI estimate from metric measurements.
Enter your height in centimetres and weight in kilograms to calculate body mass index and an adult BMI category. BMI is a screening estimate, not a diagnosis or medical advice; it does not account for factors such as age, sex, pregnancy, body composition, or health history. Speak with a qualified healthcare professional about personal health concerns.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
How is BMI calculated?
BMI is calculated as weight in kilograms divided by height in metres squared. This calculator converts the height you enter in centimetres to metres before applying that formula.
What do the BMI categories mean?
For adults, this tool labels a BMI below 18.5 as underweight, 18.5 to under 25 as normal weight, 25 to under 30 as overweight, and 30 or higher as obesity. These are screening categories, not a diagnosis.
Can BMI tell me whether I am healthy?
No. BMI is one screening estimate and does not account for factors such as age, sex, pregnancy, body composition, ethnicity, fitness, or health history. Discuss personal health questions or concerns with a qualified healthcare professional.
Do my height and weight leave my browser?
No. The calculation runs locally in your browser. CodeASystem does not upload or store the height or weight you enter.