BMI Calculator
Calculate your Body Mass Index instantly with our free, accurate BMI calculator. Supports both metric (kg/cm) and imperial (lbs/ft) units. Get BMI categories and health insights.
Use this free online BMI calculator to determine your body mass index. Enter your height and weight in your preferred units to get instant results with BMI categories and health recommendations.
BMI Calculator
Calculate your Body Mass Index and understand your weight status
Understanding BMI
What is BMI?
Body Mass Index (BMI) is a widely used screening tool that estimates whether a person has a healthy body weight for their height. It's calculated by dividing a person's weight in kilograms by the square of their height in meters (kg/m²).
BMI was developed in the 1830s by Belgian statistician Adolphe Quetelet and has been used by healthcare professionals for decades as a quick and easy way to assess potential health risks associated with being underweight, overweight, or obese.
Note: BMI is a screening tool, not a diagnostic tool. It doesn't measure body fat directly or account for factors like muscle mass, bone density, or overall body composition.
How is BMI Calculated?
Formula:
Metric System:
- • Weight in kilograms (kg)
- • Height in meters (m)
- • Example: 70 kg ÷ (1.75 m)² = 22.9
Imperial System:
- • Weight in pounds (lbs)
- • Height in inches (in)
- • Formula: (weight × 703) ÷ height²
- • Example: (154 lbs × 703) ÷ (69 in)² = 22.7
BMI Categories
Underweight
Below 18.5May indicate malnutrition, eating disorders, or other health conditions. Consult with a healthcare provider.
Normal Weight
18.5 - 24.9Generally considered a healthy weight range. Maintain your current lifestyle and regular physical activity.
Overweight
25.0 - 29.9May increase risk of health problems. Consider lifestyle changes including diet and exercise.
Obese
30.0 and aboveSignificantly increased risk of health problems. Consult with a healthcare provider for weight management strategies.
Limitations of BMI
What BMI Doesn't Account For:
- • Muscle Mass: Athletes may have high BMI due to muscle, not fat
- • Bone Density: Dense bones can increase weight
- • Body Composition: Doesn't distinguish between fat and muscle
- • Fat Distribution: Doesn't show where fat is stored
- • Age and Gender: Different populations may have different healthy ranges
- • Ethnicity: Some ethnic groups may have different risk patterns
Who Should Be Cautious:
- • Athletes and bodybuilders
- • Elderly individuals (muscle loss with age)
- • Children and adolescents (use age-specific charts)
- • Pregnant or breastfeeding women
- • People with certain medical conditions
Health Implications
Health Risks of High BMI:
- • Type 2 diabetes
- • Heart disease and stroke
- • High blood pressure
- • Sleep apnea
- • Certain types of cancer
- • Osteoarthritis
- • Gallbladder disease
Health Risks of Low BMI:
- • Malnutrition
- • Weakened immune system
- • Osteoporosis
- • Anemia
- • Fertility issues
- • Increased risk of infections
- • Delayed wound healing
When to Consult a Healthcare Provider
Important: BMI is a screening tool, not a diagnostic tool. Always consult with a healthcare provider for personalized health advice.
Consider seeing a healthcare provider if:
- • Your BMI is outside the normal range (18.5-24.9)
- • You're experiencing unexplained weight changes
- • You have concerns about your weight or health
- • You're planning to make significant lifestyle changes
- • You have a family history of weight-related health conditions
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