BMI Calculator
Calculate your Body Mass Index instantly. Find out which category you fall in and see your healthy weight range.
Your BMI
What Is BMI?
Body Mass Index (BMI) is a widely used screening tool that estimates whether your weight is appropriate for your height. It's calculated as weight divided by height squared. While BMI doesn't directly measure body fat, it correlates strongly with body fat levels for most people and is used by healthcare providers worldwide.
BMI Categories
- Underweight: BMI below 18.5 — may indicate nutritional deficiency or health issues
- Normal weight: BMI 18.5–24.9 — associated with the lowest health risks
- Overweight: BMI 25–29.9 — increased risk for cardiovascular disease and diabetes
- Obese (Class I): BMI 30–34.9 — high health risk
- Obese (Class II): BMI 35–39.9 — very high health risk
- Obese (Class III): BMI 40+ — extremely high health risk
The BMI Formula
Metric: BMI = weight (kg) ÷ height (m)²
Imperial: BMI = 703 × weight (lb) ÷ height (in)²
Limitations of BMI
BMI is a useful screening tool but has important limitations:
- It doesn't distinguish between muscle and fat — very muscular individuals may have a "high" BMI despite being healthy
- It doesn't account for fat distribution (belly fat is more dangerous than hip/thigh fat)
- It may not be accurate for older adults (who naturally lose muscle mass) or very tall/short individuals
- It doesn't measure body composition — consider a body fat calculator for a more complete picture
Despite these limitations, BMI remains a quick and useful starting point for assessing healthy weight. For a more complete assessment, combine it with waist circumference and body fat percentage.