BMI calculator
The Body Mass Index (BMI) relates your body weight to your height. It provides a rough orientation for assessing your weight.
How to calculate your BMI
With this calculator, you can quickly and easily calculate your Body Mass Index (BMI). The BMI relates your body weight to your height and provides a rough guide for assessing your weight. Follow these simple steps:
Select gender
Choose your gender, as this is considered in BMI interpretation.
Enter age
Enter your age (18-99 years). In older age, slightly different BMI evaluation standards apply.
Enter height
Enter your height in centimeters (100-250 cm). Measure preferably barefoot and standing upright.
Enter weight
Enter your current body weight in kilograms (30-300 kg). Ideally weigh yourself in the morning after using the toilet.
Calculate BMI
Click "Calculate BMI" to get your result.
Analyze result
The tool shows you your BMI value, the corresponding weight category, and a color-coded classification on the BMI scale.
Understand interpretation
Read the medical assessment and recommendations for your BMI value.
New calculation
With the "New calculation" button, you can quickly perform additional BMI calculations.
BMI Calculator โ Determine Your Body Mass Index
The BMI calculator is a scientifically based tool for calculating and evaluating your Body Mass Index. With individual interpretation based on age and gender, this calculator helps assess your weight status according to WHO standards.WHO Standard Categories
Evaluation according to internationally recognized guidelines with 4 weight categories.Individual Interpretation
Considers age and gender for more precise evaluation of your BMI value.Visual Representation
Interactive BMI scale shows your position in the weight categories.Why is BMI Important?
The Body Mass Index is an established metric for weight assessment. The BMI Calculator helps evaluate weight status and provides orientation for health measures through internationally recognized categorization.- Quick Weight Assessment: Objective evaluation in seconds according to WHO criteria
- Age and Gender-Specific: Adjusted interpretation for more accurate assessment
- Health Orientation: Detection of underweight, normal weight, overweight, and obesity
- Scientifically Founded: Based on established medical standards since the 1830s
- Visual Classification: Interactive scale shows position in the spectrum
- Practical Recommendations: Concrete action advice based on BMI category
Use Cases for the BMI Calculator
๐ฅ Health Prevention
Use the BMI calculator for regular weight checks as part of health prevention. BMI provides initial indications of possible health risks from under- or overweight and helps with early detection of need for action.๐ฏ Weight Management
When losing or gaining weight, BMI is a helpful guideline for goal setting. Calculate your current BMI and define realistic target values in the healthy range. Track your progress through regular measurements.๐ช Fitness & Sports
Athletes and fitness enthusiasts use BMI as a baseline for training plans. Note that BMI reaches its limits with high muscle mass โ combine it with other measurements like body fat percentage for a complete picture.Tips for Using the BMI Calculator
- Measure Accurately: Weigh yourself in the morning after using the toilet and before breakfast for consistent values. Measure height barefoot against a wall with a straight back.
- Regular Monitoring: Calculate your BMI monthly for progress tracking. Individual values can fluctuate โ the trend over several months is more meaningful.
- Know BMI Limitations: BMI does not distinguish between muscle and fat mass. Athletes with high muscle mass may have an elevated BMI without being overweight. If in doubt, also measure body fat percentage.
- Consider Age Adjustment: At older ages (over 65 years), slightly elevated BMI values between 25-29 are often harmless and may even be associated with longer life expectancy.
- Medical Consultation: BMI is a reference value, not a diagnosis. For abnormal values, health complaints, or uncertainties, always consult a doctor for a comprehensive assessment.
Frequently Asked Questions (FAQ)
BMI (Body Mass Index) is calculated by dividing body weight in kilograms by the square of height in meters (BMI = kg/mยฒ). For a person weighing 70 kg and 1.75 m tall, the result is: 70 รท (1.75 ร 1.75) = 22.9. This simple formula was already developed in the 1830s.
WHO defines four main categories: Underweight (BMI < 18.5), Normal weight (BMI 18.5-24.9), Overweight (BMI 25-29.9), and Obesity (BMI โฅ 30). Obesity is further subdivided into Grade I (30-34.9), Grade II (35-39.9), and Grade III (โฅ 40). These categories serve as international standards for weight classification.
No, BMI has limitations. It does not distinguish between muscle and fat mass, so athletes with high muscle mass may be incorrectly classified as overweight. Body structure, bone density, and ethnic differences are also not considered. BMI is only of limited use for children, pregnant women, and very muscular people.
Body composition changes with age: muscle mass decreases, body fat percentage increases. For people over 65, BMI values between 25-29 may be optimal. Women naturally have a higher body fat percentage than men. Therefore, BMI should always be interpreted in the context of age and gender.
Both underweight (BMI < 18.5) and obesity (BMI โฅ 30) are associated with increased health risks. At BMI above 30, the risk of cardiovascular diseases, type 2 diabetes, joint problems, and certain cancers increases. Underweight can lead to malnutrition, weakened immune system, and osteoporosis. The healthiest range is 18.5-24.9.
For overweight, balanced nutrition with caloric deficit, regular exercise (at least 150 minutes per week), and behavioral changes help. For underweight, calorie-rich, nutrient-dense meals and targeted strength training make sense. Important: Set realistic goals (0.5-1 kg weight change per week) and seek medical advice for severe under- or overweight.
For a more accurate assessment: body fat percentage measurement (e.g., with caliper or bioimpedance analysis), waist circumference (men > 94 cm, women > 80 cm increases risk), waist-hip ratio (WHR), or waist-height ratio (WHtR). These methods consider fat distribution, which is more important for health risks than total weight.
With normal weight, an annual check for prevention is sufficient. During active weight management (losing or gaining), monthly BMI calculation is recommended. More important than individual values is the trend over several months. Always weigh yourself under the same conditions (morning, fasting, after toilet) for comparable values.
Studies show that Asian populations have a higher body fat percentage at the same BMI and thus higher health risks than Europeans. Therefore, lower thresholds sometimes apply for Asians: overweight from BMI 23, obesity from BMI 27.5. These ethnic differences are not considered in standard BMI but are medically relevant.
No, BMI is a screening tool, not a medical diagnosis. It provides initial indications of weight status but does not consider individual health factors, body composition, or comorbidities. For abnormal BMI values, health complaints, or to create an individual nutrition and exercise plan, always consult a doctor or nutritionist.