For most adults, a BMI of 30 or higher is considered obese.

Quick answer

  • Underweight: BMI less than 18.5
  • Normal weight: BMI 18.5–24.9
  • Overweight: BMI 25–29.9
  • Obese: BMI 30 or more

Many health organizations, including the World Health Organization, define obesity in adults as a BMI of at least 30 kg/m².