👤 BMI Calculator
Calculate body mass index from height and weight.
Calculate your body mass index
Enter your measurements or describe them to the AI assistant. Both modes use the same calculation.
Your measurements
Switch measurement units whenever you need.
BMI updates automatically when height or weight changes.
Health note: Adult BMI is a screening measure, not a medical diagnosis. BMI does not distinguish between fat, muscle, and bone, and does not replace advice from a qualified healthcare professional.
About this calculator
This calculator is designed to provide clear, easy-to-understand results. Enter your values, review the results, and calculate again whenever you need to.
BMI formula
For metric measurements, BMI = weight in kilograms ÷ height in meters squared (kg/m²). For US customary measurements, BMI = 703 × weight in pounds ÷ height in inches squared. Use accurate height and weight measurements and the correct units.
How to interpret the result
BMI is a screening measure, not a diagnosis. It does not directly measure body fat and may not reflect differences in muscle mass, age, pregnancy or individual health. Adult interpretation differs from interpretation for children and teens, which uses age- and sex-specific percentiles.
Use BMI as one piece of context
If you are concerned about weight or health, consider discussing the result with a qualified healthcare professional who can account for your history and other measures. Do not use a calculator result alone to make a medical decision.
Frequently asked questions
What does BMI mean?
Body mass index relates weight to height as a general screening measure; it is not a medical diagnosis.