A BMI (Body Mass Index) calculator computes a measure of body weight relative to height using the formula BMI = weight (kg) / height² (m²).
About this calculator
A BMI (Body Mass Index) calculator computes a measure of body weight relative to height using the formula BMI = weight (kg) / height² (m²). BMI is commonly used as a screening tool to identify potential weight-related health risks.
While BMI is a useful population-level screening tool, it does not directly measure body fat percentage or distinguish between muscle and fat. Athletes with high muscle mass may have a high BMI without excess body fat.
Common uses
- Check if your weight is in a healthy range for your height
- Track BMI changes over a weight loss or gain program
- Understand the minimum and maximum healthy weight for your height
- Screen for potential weight-related health risks
Frequently asked questions
What are the BMI categories?
BMI categories: Underweight (below 18.5), Normal/Healthy (18.5–24.9), Overweight (25.0–29.9), Obese Class I (30.0–34.9), Obese Class II (35.0–39.9), Obese Class III (40.0 and above). The World Health Organization and most health bodies use these categories.
Is BMI accurate for everyone?
BMI has limitations. It overestimates body fat in muscular individuals like athletes (who may have a high BMI but low body fat). It underestimates body fat in older adults who have lost muscle. It may not be equally applicable across all ethnicities. Always interpret BMI in context with other health metrics.
What BMI is considered obese?
A BMI of 30 or above is classified as obese. Obesity is associated with increased risk of type 2 diabetes, heart disease, stroke, certain cancers, and other health conditions. BMI above 40 is classified as severe or morbid obesity.