Body Mass Index (BMI) Calculator

What is BMI?

Body Mass Index (BMI) is a measure that uses your height and weight to estimate whether you are at a healthy weight. It is calculated by dividing your weight in kilograms by your height in meters squared. Doctors and health organizations worldwide use BMI as a quick screening tool, though it works best alongside other measurements.

BMI Categories

• Underweight: BMI < 18.5
• Normal: BMI 18.5 - 24.9
• Overweight: BMI 25.0 - 29.9
• Obesity: BMI ≥ 30.0

BMI limitations

BMI is a useful starting point, but it has blind spots. It cannot tell the difference between muscle and fat — a lean, muscular person may register as "overweight" while someone with low muscle mass and higher body fat could show as "normal." Age, gender, and ethnicity also influence what a healthy weight looks like.

For a more complete picture, consider checking your body fat percentage or using our Ideal Body Weight Calculator which compares four published formulas (Devine, Robinson, Miller, and Hamwi) to give you a realistic target weight range.

What to do with your result

If your BMI is outside the normal range, the next step is understanding your calorie needs. Our Daily Calorie Intake Calculator shows how many calories you need to maintain, lose, or gain weight based on your activity level. For a structured approach to reaching a healthier weight, try the Weight Loss Calculator — it builds a personalized timeline with milestones so you can track progress week by week.