BMI Calculator
Enter your height in centimeters
Enter your weight in kilograms
Calculate your Body Mass Index (BMI) to determine if your weight is in a healthy range for your height.
What is BMI?
Body Mass Index Explained
Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It is calculated by dividing a person's weight in kilograms by the square of their height in meters.
Why BMI Matters
BMI is a useful screening tool, but it's just one factor for assessing health status.
How to Use
- Select your unit system (metric or imperial)
- Enter your height and weight
- Click "Calculate BMI" to see your result
- Review your BMI category and recommendations
BMI Categories
BMI Calculator
Calculate your Body Mass Index (BMI) to determine if your weight is in a healthy range for your height.
Enter your height in centimeters
Enter your weight in kilograms
What is BMI?
Body Mass Index Explained
Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It is calculated by dividing a person's weight in kilograms by the square of their height in meters. BMI is widely used as a screening tool to categorize individuals into different weight status categories.
Developed by Belgian mathematician Adolphe Quetelet in the 1830s, BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients.
Why BMI Matters
While BMI is a useful indicator for most people, it's important to remember that it's just one tool among many for assessing health status. BMI doesn't directly measure body fat percentage or distinguish between muscle and fat mass.
How to Use the BMI Calculator
Step-by-Step Instructions
- 1Select your preferred unit system (metric or imperial)
- 2Enter your height in centimeters or feet/inches
- 3Enter your weight in kilograms or pounds
- 4Click the "Calculate BMI" button to see your result
- 5Review your BMI category and health recommendations
Tips for Accurate Results
- Measure your height without shoes for accuracy
- Weigh yourself in the morning before eating
- Use consistent units throughout the calculation
- Round measurements to the nearest decimal place
- Take measurements on a flat, hard surface
- Ensure your scale is calibrated properly
BMI Categories
The World Health Organization (WHO) has established the following BMI categories for adults:
| BMI Range | Category | Health Risk | Recommendations |
|---|---|---|---|
| Below 18.5 | Underweight | Increased risk of nutritional deficiency | Consult healthcare provider for weight gain plan |
| 18.5 - 24.9 | Normal weight | Lowest health risk | Maintain current lifestyle and weight |
| 25.0 - 29.9 | Overweight | Increased risk of health problems | Consider diet and exercise modifications |
| 30.0 and above | Obese | High risk of health problems | Seek medical advice for weight management |
BMI Formula
BMI is calculated using simple mathematical formulas that vary depending on the unit system you use:
Metric Formula
Where:
- • Weight is in kilograms (kg)
- • Height is in meters (m)
Example:
Weight: 70 kg, Height: 1.75 m
BMI = 70 ÷ (1.75)² = 22.9
Imperial Formula
Where:
- • Weight is in pounds (lbs)
- • Height is in inches (in)
- • 703 is the conversion factor
Example:
Weight: 154 lbs, Height: 69 in
BMI = (154 ÷ 69²) × 703 = 22.7
Health Implications
Understanding your BMI category can help you assess potential health risks and take appropriate action:
Underweight (BMI < 18.5)
Being underweight may indicate malnutrition, eating disorders, or other health conditions.
Potential Health Risks:
- Weakened immune system
- Osteoporosis and bone fractures
- Fertility issues
- Delayed wound healing
- Increased risk of infections
Normal Weight (BMI 18.5-24.9)
This range is associated with the lowest risk of health problems and is considered optimal for most adults.
Health Benefits:
- Lower risk of chronic diseases
- Better cardiovascular health
- Improved energy levels
- Better sleep quality
- Enhanced mobility and flexibility
Overweight (BMI 25-29.9)
Being overweight increases the risk of developing several health conditions.
Increased Risk Of:
- Type 2 diabetes
- High blood pressure
- Heart disease
- Certain cancers
- Sleep apnea
- Stroke
Obese (BMI ≥ 30)
Obesity significantly increases the risk of serious health conditions and may reduce life expectancy.
Serious Health Risks:
- Heart disease and stroke
- Type 2 diabetes
- Certain types of cancer
- Sleep apnea
- Osteoarthritis
- Fatty liver disease
- Kidney disease
- Pregnancy complications
Limitations of BMI
Important Note:
While BMI is a useful screening tool, it has several limitations and should not be the only factor used to assess health status.
Key Limitations
Doesn't distinguish between muscle and fat
Athletes with high muscle mass may have high BMI but low body fat percentage.
Doesn't account for fat distribution
Abdominal fat is more dangerous than fat stored in other areas of the body.
Age and gender differences
BMI doesn't account for natural changes in body composition with age or gender differences.
Ethnicity considerations
Different ethnic groups may have different health risks at the same BMI level.
Better Assessment Methods
Additional Measurements
- Waist circumference
- Body fat percentage
- Waist-to-hip ratio
- Muscle mass assessment
Professional Evaluation
- Blood pressure monitoring
- Cholesterol levels
- Blood sugar tests
- Overall fitness assessment
Recommendation
For a complete health assessment, BMI should be used alongside other measurements like waist circumference, body fat percentage, and overall health evaluation by a healthcare professional. Always consult with your doctor for personalized health advice.