Calculate your Body Mass Index (BMI) from height and weight. Switch between metric (kg/cm) and imperial (lbs/ft/in) units and see your BMI category update instantly with a visual scale indicator.
Frequently Asked Questions
What is BMI?
Body Mass Index (BMI) is a measure of body fat based on height and weight. It is calculated as weight in kilograms divided by height in metres squared (kg/m²).
What are the BMI categories?
Under 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30 or above is obese. These are standard WHO categories for adults.
Is BMI accurate for everyone?
BMI is a screening tool, not a diagnostic measure. It may not accurately reflect body composition for athletes, elderly people, or those with high muscle mass. Consult a healthcare professional for personalised advice.
Can I calculate my age?
Yes. Use the Age Calculator to find your exact age in years, months, and days.
Is this tool free and does it work on mobile?
Yes on both counts. The BMI Calculator on draft21 is completely free with no sign-up required and works on all devices.