BMI Calculator
Calculate your Body Mass Index (BMI) instantly. Supports US (imperial) and metric units. Get your BMI score, health category, healthy weight range, and more.
BMI Calculator
Body Mass Index — Adults
lb
Your BMI
23.6
✓ Normal Weight
BMI Scale
1518.5253040
| Category | BMI Range | Status |
|---|---|---|
| Underweight | < 18.5 | — |
| Normal Weight | 18.5 – 24.9 | ✓ You |
| Overweight | 25.0 – 29.9 | — |
| Obese | 30.0 and above | — |
Healthy Weight Range
125 – 168 lbs
BMI Prime
0.94
Ponderal Index
12.9
Weight to Lose/Gain
None ✓
📊 BMI Categories Chart
Medical Disclaimer: BMI is a screening tool, not a diagnostic measure. Always consult a healthcare professional for medical advice about your weight and health.
What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your height and weight. Widely used by healthcare professionals as a quick screening tool, BMI categorizes individuals into weight status categories — underweight, normal weight, overweight, and obese. While BMI is not a perfect measure of body fat, it is a useful starting point for assessing weight-related health risks. For a more complete picture, also try our body fat calculator, calorie calculator, and BMR calculator.
📐 BMI Formula
US / Imperial:
BMI = 703 × weight(lb) / height(in)²
Metric:
BMI = weight(kg) / height(m)²
Both formulas produce the same result when units are consistent. Example: 5'9", 160 lbs → BMI = 23.6
⚠️ Limitations of BMI
- Athletes: May have high BMI due to muscle mass, not fat
- Elderly: May have normal BMI but high body fat due to muscle loss
- Pregnancy: BMI is not applicable during pregnancy
- Children: Different BMI charts are used for ages 2–19
- Ethnicity: Asian populations may have higher health risks at lower BMI values
- Body shape: Waist circumference matters — apple vs pear body shape
💚 Maintaining a Healthy BMI
- Balanced diet: Whole foods, vegetables, lean proteins, and healthy fats
- Regular exercise: At least 150 minutes of moderate activity per week
- Strength training: Builds muscle, increases metabolism
- Sleep: Poor sleep increases hunger hormones and promotes weight gain
- Stress management: Chronic stress leads to cortisol-driven weight gain
- Hydration: Sometimes thirst is mistaken for hunger
Track your daily calorie needs with our calorie calculator.
📊 BMI vs Other Measurements
- Waist-to-Hip Ratio: Better predictor of cardiovascular risk than BMI alone
- Body Fat %: Most accurate measure of body composition — use our body fat calculator
- Waist Circumference: Men above 40 inches, women above 35 inches — high risk
- Waist-to-Height Ratio: Should be below 0.5 for good health
- BMR: Know how many calories your body burns at rest — BMR calculator
Frequently Asked Questions About BMI
According to the World Health Organization (WHO), a healthy BMI for adults is between 18.5 and 24.9. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese. These thresholds may vary slightly for different ethnic groups — for example, some Asian health organizations recommend a lower threshold of 23 for overweight.
To calculate BMI in US units: multiply your weight in pounds by 703, then divide by your height in inches squared. For example, a person who is 5'9" (69 inches) and weighs 160 lbs: BMI = 703 × 160 / (69 × 69) = 23.6. Use our BMI calculator above to get instant results without the math.
The BMI formula and standard categories are the same for adult men and women. However, women naturally have a higher body fat percentage than men at the same BMI. For a sex-specific body composition measurement, use our body fat calculator which accounts for gender differences.
A BMI of 30 or higher is classified as obese. Obesity is further divided into Class I (BMI 30–34.9), Class II (35–39.9), and Class III/Severe Obesity (40+). Higher obesity classes are associated with greater health risks including type 2 diabetes, heart disease, and sleep apnea.
Yes — athletes and highly muscular individuals often have a high BMI due to dense muscle mass, not excess fat. Conversely, someone with a "normal" BMI can still have high body fat percentage (called "skinny fat"). BMI should be considered alongside other health indicators like blood pressure, cholesterol, and waist circumference. Use our body fat calculator for a more complete assessment.