Free BMI Calculator
Body Mass Index (BMI) is a convenient indicator of body fatness and overall health based on your height and weight. Use this online tool to classify your weight category and discover your target ranges.
Calculation Output
• Healthy range weight: 54.7kg - 73.7kg
• BMI is a screening metric and doesn't account for direct muscle/fat ratio.
Need personalized meal & training plans?
Get App to Track TrendsStandard BMI Classifications
According to the World Health Organization (WHO) and National Institutes of Health (NIH), adult body weight is classified into the following four standard ranges:
| BMI Range (kg/m²) | Weight Status Category |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Normal / Healthy Weight |
| 25.0 – 29.9 | Overweight |
| 30.0 or Higher | Obesity |
Limitations of BMI
Although BMI correlates strongly with clinical health risks, it is not a direct measure of body fat. For athletes, heavy weight lifters, and older individuals, BMI can sometimes overestimate fatness (due to dense muscle tissue) or underestimate it (due to muscle loss). Use BMI as a baseline step alongside muscle ratio telemetry.
Track Trends with Health Tractal
Knowing your BMI is the first step. Maintain weight logs, plan calorie budgets, and configure automated hydration targets from our Android app widget.
Frequently Asked Questions (FAQ)
What is Body Mass Index (BMI)?
Body Mass Index (BMI) is a clinical calculation that uses your height and weight to estimate overall body fatness and screen for weight-related health risks.
What is a healthy BMI range?
For most adults, a healthy BMI is between 18.5 and 24.9. A BMI below 18.5 is considered underweight, 25.0 to 29.9 is overweight, and 30.0 or higher indicates obesity.
How accurate is the BMI calculation?
While BMI is a quick screening tool, it does not distinguish between weight from fat, bone mass, or muscle. Muscle is denser than fat, so athletic individuals or bodybuilders may have a high BMI despite low body fat levels. Use BMI as a baseline alongside other indicators.
How do I calculate BMI manually?
The formula for BMI is weight in kilograms divided by height in meters squared: BMI = weight (kg) / height (m)². For example, if you weigh 70 kg and are 1.75 meters tall, the calculation is 70 / (1.75 * 1.75) = 22.86.