BMI Calculator – Calculate Body Mass Index

Calculate BMI – What does your Body Mass Index really say?

Whether at a check-up, a doctor's visit, or in a fitness app: The Body Mass Index (BMI)has been the worldwide standard for assessing body weight for decades. With our BMI Calculator you can determine within seconds whether you are underweight, normal weight, or overweight.

But what exactly is hidden behind this number? Does the BMI apply equally to women and men? And why does the formula reach its limits, especially for strength athletes? In this guide you will learn everything you need to know about calculating your BMI.

How is the BMI calculated? (The Formula)

A calculation example: If you weigh 75 kilograms and are 1.80 meters tall, calculate 1.80 x 1.80 = 3.24. If you now divide 75 by 3.24, you get a BMI of 23.1. According to WHO guidelines, this puts you exactly in the normal weight range.

Since manual calculation is prone to errors, our digital BMI Calculator above does this fully automatically for you.

The WHO BMI Table: When are you overweight?

The World Health Organization (WHO) has categorized the BMI into clear classes. These generally apply to adults 19 years and older.

• Under 18.5: Underweight (Health risk from nutrient deficiency possible)
• 18.5 to 24.9: Normal weight (The ideal goal for general health)
• 25.0 to 29.9: Pre-obesity / Slight overweight
• 30.0 to 34.9: Obesity Class I (Increased risk for cardiovascular diseases)
• Over 35.0: Obesity Class II and III (Severe overweight)

Are you in the overweight range? Use our Calorie Calculator to find out with what calorie deficit you can lose weight healthily and sustainably.

Are there differences in BMI for women and men?

Although the WHO table is gender-neutral, many doctors and nutritionists use gender-specific adaptations. The reason: Men naturally have a higher muscle mass than women.

For men, the ideal is a BMI in the range of 20 to 25. For women, the ideal range is set slightly lower, often between 19 and 24. Age also plays a role. With increasing age (from about 40 years on), the threshold for normal weight shifts slightly upwards, as the metabolism slows down and a slight "cushion" serves evolutionarily as a reserve.

The weakness of the BMI: Why strength athletes are often considered "overweight"

The BMI has one crucial blind spot: It does not distinguish between muscle mass and body fat. The formula only knows the raw total weight on the scale.

A professional bodybuilder with an extremely low body fat percentage of 8% might weigh 100 kg at a height of 1.80m. His BMI is over 30. According to the WHO table, he is "obese" – a look in the mirror, however, reveals the exact opposite. Muscles are denser and heavier than fat.

Tip for athletes: If you have a lot of muscle mass, the BMI is useless for you. Instead, use our Body Fat Percentage Calculator (Navy Method)or the Waist-to-Hip Ratio (WHR) Calculatorto evaluate your health more accurately.

BMI Conclusion: A good guideline, but not the final word

In summary, the Body Mass Index is a fantastic, fast screening tool for the general population. It requires no equipment and can be calculated immediately.

However, if your BMI is mildly elevated, don't panic. First, evaluate your lifestyle: Do you exercise regularly? Is your waist circumference in the normal range? If so, then a BMI of 26 could be completely healthy for you. But if your goal is fat loss, we recommend that you now calculate your protein needsto optimally protect your muscles during the diet!