Calculator
BMI calculator.
Enter your height and weight to see your Body Mass Index and where it sits on the standard World Health Organization weight-status scale. Switch between metric and imperial units freely. Nothing you type here is saved or sent anywhere.
- kg ÷ m² formula
- 18.5–25 normal range
- Metric & imperial
Your measurements
Your BMI updates automatically as you type.
Your result
What BMI is
Body Mass Index is a single number derived from your height and weight. It was designed as a quick way to screen populations into broad weight-status bands. It is widely used because it is simple to calculate and easy to compare.
The formula
BMI = weight (kg) ÷ height (m)². If you enter imperial measurements, this calculator converts them to metric before applying the same formula.
The standard categories
- Underweight: BMI below 18.5
- Normal weight: BMI 18.5 to 24.9
- Overweight: BMI 25 to 29.9
- Obese: BMI 30 and above
What BMI does not tell you
BMI does not distinguish muscle from fat, does not account for where weight is carried, and does not reflect fitness, bone density, or overall health. Athletes and very muscular people often read as overweight despite low body fat. Treat the number as one rough signal among many, not a verdict.
Educational screening tool. Not medical advice. BMI is a population-level screening number and cannot diagnose any condition. It is not a measure of health, and it is not an eligibility check for any program or treatment. For questions about your health, talk with a licensed physician. If this is a medical emergency, call 911.