Advanced BMI Calculator
Calculate your Body Mass Index and understand your results
BMI Results
Your BMI
Weight Category
Healthy Weight Range
BMI Categories
| BMI Range | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Increased risk |
| 18.5 – 24.9 | Normal weight | Lowest risk |
| 25 – 29.9 | Overweight | Increased risk |
| 30 and above | Obese | High risk |
What is BMI?
Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight, and obesity in adults. It is defined as a person’s weight in kilograms divided by the square of their height in meters (kg/m²).
BMI provides a useful population-level measure of overweight and obesity, as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals.
Why Use Our BMI Calculator?
Instant Results
Get accurate BMI calculations in seconds with our advanced algorithm
Dual Measurement Systems
Calculate using both metric and imperial measurement systems
Health Insights
Get personalized health recommendations based on your BMI results
Privacy Focused
Your data never leaves your browser – calculations happen locally
How to Use Our BMI Calculator
Select Measurement System
Choose between metric (kg, cm) or imperial (pounds, feet/inches) units using the tabs
Enter Your Measurements
Input your height and weight using the input fields or sliders for precise control
Calculate
Click the calculate button to see your BMI results and health category
Review Results
Examine your BMI category, healthy weight range, and health recommendations
Understanding Your BMI Results
BMI categories are based on the World Health Organization’s (WHO) classifications:
- Underweight (BMI below 18.5): May indicate insufficient weight for height
- Normal weight (BMI 18.5-24.9): Generally considered healthy for most people
- Overweight (BMI 25-29.9): May indicate excess weight for height
- Obesity (BMI 30 and above): Indicates significantly excess weight for height
It’s important to remember that BMI is a screening tool, not a direct measure of body fat or health. Factors like muscle mass, bone density, and distribution of fat can affect BMI interpretation.
Frequently Asked Questions
BMI is a useful screening tool but has limitations. It doesn’t directly measure body fat, so athletes with high muscle mass may have a high BMI but low body fat. Similarly, older adults may have a normal BMI but higher body fat. For most people, BMI provides a reasonable estimate of weight-related health risks.
Yes, research suggests that health risks may begin at lower BMI levels for some ethnic groups. For example, Asian populations may experience health risks at lower BMI levels than Caucasians. Some health organizations recommend lower BMI thresholds for these populations.
BMI is calculated the same way for children and adults, but the interpretation is different for those under 20. For children and teens, BMI is age- and sex-specific and is referred to as BMI-for-age. Our calculator is designed for adults aged 20 years and older.
BMI doesn’t distinguish between muscle and fat, so it may overestimate body fat in athletes and underestimate it in older adults with muscle loss. It also doesn’t account for fat distribution, which is important for health risks. Waist circumference and other measurements can provide additional information.
If your BMI is outside the normal range, consult with a healthcare professional for a comprehensive health assessment. They can help you understand your results in context and develop a personalized plan if needed. Remember that BMI is just one indicator of health.