Measure your weight in kilograms or pounds
Measure your height in meters or inches
Use the BMI formula: BMI = weight ÷ height²
If using metric units, calculate BMI = kg ÷ m²
If using imperial units, calculate BMI = (lb ÷ in²) × 703
Compare the result to BMI categories
Underweight: less than 18.5
Normal weight: 18.5 to 24.9
Overweight: 25 to 29.9
Obesity: 30 or higher