BMI Calculator
Calculate your Body Mass Index and understand your weight category
Your BMI
BMI Scale
BMI Prime
Ratio to upper normal limit
Healthy Weight Range
- kg
For your height (BMI 18.5-24.9)
Est. Body Fat
%
Deurenberg formula estimate
BMI Categories (WHO)
| Category | BMI Range |
|---|---|
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About BMI Calculator
The Body Mass Index (BMI) is a simple and widely used method to estimate body fat based on height and weight. While not a direct measure of body fat, BMI provides a useful screening tool to identify potential weight-related health issues.
How BMI is Calculated
Metric Formula: BMI = weight (kg) ÷ height (m)²
Imperial Formula: BMI = (weight (lbs) ÷ height (inches)²) × 703
Source: World Health Organization (WHO), Centers for Disease Control and Prevention (CDC)
BMI Categories (WHO)
| Category | BMI Range |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5 - 24.9 |
| Overweight | 25 - 29.9 |
| Obese Class I | 30 - 34.9 |
| Obese Class II | 35 - 39.9 |
| Obese Class III | ≥ 40 |
Body Fat Percentage Estimate
The body fat percentage is estimated using the Deurenberg formula:
Formula: Body Fat % = (1.20 × BMI) + (0.23 × Age) - (10.8 × sex) - 5.4
(where sex = 1 for male, 0 for female)
Source: Deurenberg et al., British Journal of Nutrition (1991), PMID: 2043597
Gender Differences in Body Fat
- Women typically have about 10% more body fat than men at the same BMI
- Men: Healthy body fat range is 18-24%
- Women: Healthy body fat range is 25-31%
Source: NCBI research, Medical News Today
Important Limitations
While BMI is a useful screening tool, it has several limitations:
- Muscle mass: BMI doesn't distinguish between muscle and fat. Athletes and bodybuilders may have high BMI but low body fat
- Age: Older adults may have more body fat than younger adults with the same BMI
- Ethnicity: Different ethnic groups may have different body fat levels at the same BMI
- Pregnancy: BMI is not applicable during pregnancy
Disclaimer: This calculator is for informational purposes only and should not be used as a substitute for professional medical advice. Consult with a healthcare professional for personalized guidance about your weight and health.
About the Formulas
BMI Formula (WHO)
BMI = Weight (kg) ÷ Height² (m²)
Source: World Health Organization
Body Fat Percentage (Deurenberg Formula)
BF% = (1.20 × BMI) + (0.23 × Age) - (10.8 × Sex) - 5.4
Sex: 1 for male, 0 for female | Source: Deurenberg et al., 1991
⚠️ Limitations
- BMI doesn't distinguish between muscle and fat mass
- Not suitable for athletes with high muscle mass
- May not be accurate for elderly individuals
- Different thresholds may apply for some ethnic groups
- Body fat estimation is approximate - use DEXA scan for accuracy