BMI Calculator
Calculate your Body Mass Index for men, women & children with health insights
Enter your details and click Calculate BMI to see your personalized health insights.
<18.5 Normal
18.5–24.9 Overweight
25–29.9 Obese
30+
Health Tips
What is Body Mass Index (BMI)?
Body Mass Index (BMI) is a widely used screening tool that measures the relationship between your weight and height. It provides a general indicator of whether you're at a healthy weight for your height.
BMI Formula
Metric: BMI = weight (kg) ÷ height² (m²)
Imperial: BMI = (weight (lb) ÷ height² (in²)) × 703
BMI Categories (WHO Standard)
| Category | BMI Range | Health Risk |
|---|---|---|
| Severe Underweight | < 16.0 | Very High |
| Underweight | 16.0 – 18.4 | Moderate |
| Normal Weight ✅ | 18.5 – 24.9 | Low |
| Overweight | 25.0 – 29.9 | Increased |
| Obese (Class I) | 30.0 – 34.9 | High |
| Obese (Class II) | 35.0 – 39.9 | Very High |
| Severely Obese (Class III) | ≥ 40.0 | Extremely High |
Limitations of BMI
- Doesn't directly measure body fat percentage
- May overestimate body fat in athletes and muscular individuals
- May underestimate body fat in older adults who have lost muscle mass
- Doesn't account for fat distribution (waist circumference is also important)
Health Implications of a Healthy BMI
Maintaining a healthy BMI (18.5–24.9) is associated with reduced risk for heart disease, Type 2 diabetes, certain cancers, sleep apnea, and osteoarthritis.
Use our Calorie Calculator to determine your daily calorie needs, or our BMR Calculator to find your basal metabolic rate.
Frequently Asked Questions
What is a healthy BMI for women?
A healthy BMI for women is between 18.5 and 24.9. Women generally have higher body fat percentages than men at the same BMI, so some experts suggest a lower healthy range for women.
What is a good BMI for men?
A healthy BMI for men is also between 18.5 and 24.9, the universal standard. Men with high muscle mass may show higher BMI despite having low body fat.
How accurate are online BMI calculators?
Our BMI calculator uses the standard WHO formula and is highly accurate for adults aged 18–65. For children, athletes, elderly, and pregnant women, the results should be interpreted with caution.
What is BMI Prime?
BMI Prime is the ratio of your BMI to the upper limit of normal BMI (24.9). A BMI Prime of 1.0 means you are exactly at the top of the normal range. Values below 0.74 indicate underweight; above 1.0 indicates overweight or obese.