BMI Calculator

Calculate your Body Mass Index and discover your health status using WHO-standard guidelines.

Basic Information

0.0
Normal Weight
Underweight Normal Overweight Obese

WHO BMI Categories

Adults (18+)

UnderweightBMI < 18.5
Normal WeightBMI 18.5 – 24.9
OverweightBMI 25.0 – 29.9
ObeseBMI ≥ 30.0

Health Context

BMI is a screening toolNot a diagnosis
Doesn't account for muscle massUse with LMI/FFMI
Healthy range varies by ethnicityConsult your doctor

More Free Calculators

BMI LMI FFMI WHR Ideal Weight BMR & TDEE

Understanding BMI

Body Mass Index is a simple calculation using height and weight to screen for weight categories that may lead to health problems.

📊 What is BMI?

BMI is calculated by dividing weight in kilograms by height in meters squared. It's used worldwide as a quick screening tool by healthcare providers.

⚖️ BMI Limitations

BMI doesn't distinguish between muscle and fat. Athletes with high muscle mass may have a high BMI despite being in excellent health.

🎯 Health Goals

Maintaining a healthy BMI (18.5–24.9) is associated with lower risk of chronic diseases. But overall health depends on many factors beyond BMI.

💡 Next Steps

For a complete picture, combine BMI with our LMI, FFMI, and WHR calculators. Consider consulting a healthcare provider for personalized advice.

Frequently Asked Questions

What is a healthy BMI range?

According to the World Health Organization (WHO), a healthy BMI falls between 18.5 and 24.9. A BMI below 18.5 is classified as underweight, 25.0 to 29.9 is overweight, and 30.0 or above is considered obese. These thresholds may vary slightly by ethnicity — for example, some Asian populations have increased health risks at lower BMI values. BMI is a screening tool and should be interpreted alongside other health indicators.

How is BMI calculated?

BMI is calculated by dividing your weight in kilograms by your height in meters squared (kg/m²). For example, a person weighing 70 kg who is 1.75 m tall would have a BMI of 70 / (1.75 x 1.75) = 22.9, which falls in the normal weight range. The formula is the same for men and women, though interpretation may differ based on age, sex, and body composition.

Is BMI accurate for athletes?

BMI does not distinguish between muscle mass and fat mass, which means athletes and bodybuilders often receive an "overweight" or "obese" classification despite having low body fat. For physically active individuals, metrics like Fat-Free Mass Index (FFMI) and body fat percentage provide a much more accurate picture of body composition and health. We recommend using our FFMI calculator alongside BMI for a complete assessment.

What BMI is considered obese?

A BMI of 30 or above is classified as obese according to WHO standards. Obesity is further divided into three classes: Class I (BMI 30.0–34.9), Class II (BMI 35.0–39.9), and Class III or severe obesity (BMI 40.0 and above). Higher obesity classes are associated with significantly greater risk of cardiovascular disease, type 2 diabetes, and other metabolic conditions.

What is the difference between BMI and body fat percentage?

BMI is a simple ratio of weight to height and does not measure actual fat tissue. Body fat percentage measures the proportion of your total weight that is fat, providing a direct assessment of body composition. Two people with the same BMI can have very different body fat levels depending on their muscle mass. BMI is best used as an initial screening tool, while body fat percentage offers a more precise health indicator. The BodyMuse app provides photo-based body composition analysis for deeper insight.