BMI Calculator
Calculate your Body Mass Index (BMI) from your height and weight. BMI is a quick screening number that sorts adult weight into standard categories.
How BMI is calculated
BMI = weight (kg) ÷ height (m)². In US units it is 703 × weight (lb) ÷ height (in)². Both give the same number.
BMI categories (adults)
Underweight: below 18.5 · Normal weight: 18.5–24.9 · Overweight: 25–29.9 · Obese: 30 and above. These ranges apply to adults 20+ and are a general screen, not a diagnosis.
Frequently asked questions
Is BMI accurate for everyone?
BMI is a useful screen but doesn't separate muscle from fat. Very muscular people can read as 'overweight,' and it isn't meant for children, pregnancy, or the elderly. Ask a clinician for a full assessment.
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered healthy.
How do I calculate BMI by hand?
Divide your weight in kilograms by your height in meters squared, or take 703 times your weight in pounds divided by your height in inches squared.