What Is BMI and How Is It Calculated?
Body Mass Index (BMI) is a simple screening measurement that estimates whether your weight is healthy for your height. It's calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). Because it only takes two measurements, BMI is one of the fastest ways for men and women to get a general sense of their weight status.
BMI Categories Explained
- Below 18.5 - Underweight
- 18.5 to 24.9 - Healthy weight
- 25 to 29.9 - Overweight
- 30 and above - Obesity range
These ranges apply the same way to both men and women, since the formula itself does not differentiate by sex. If your result falls outside the healthy range, our guide on what your BMI number really means explains what to do next, and our calorie calculator can help you set a safe, personalized calorie target.
Limitations of BMI
BMI does not distinguish between muscle and fat, so very muscular individuals may show a higher BMI despite low body fat. It also doesn't account for where fat is stored on the body. Use it as a helpful starting point rather than a complete picture of your health, and consult a healthcare professional for personalized advice.
Frequently Asked Questions
Is this BMI calculator accurate for both men and women?
Yes, the BMI formula is identical for men and women. Some health risks associated with a given BMI can differ slightly by sex, but the calculation itself does not change.
What should I do if my BMI is outside the healthy range?
Speak with a healthcare provider for personalized guidance, and consider gradual, sustainable changes to diet and physical activity rather than extreme measures.
Does BMI work for athletes and very muscular people?
Not perfectly - muscle weighs more than fat, so muscular individuals can show a higher BMI without carrying excess body fat.