BMI Calculator

Calculate your Body Mass Index (BMI) with our free online BMI calculator. Determine if you're in a healthy weight range based on your height and weight and understand the health implications of your BMI.

How the BMI Calculator Works

Our BMI calculator uses the standard formula to calculate your Body Mass Index:

BMI Calculation

The formula used to calculate BMI is:

• BMI = weight (kg) ÷ [height (m)]²

For example, if you weigh 70 kg and your height is 175 cm (1.75 m):

• BMI = 70 ÷ (1.75)² = 70 ÷ 3.0625 = 22.9

BMI Categories

BMI values are categorized as follows:

• Below 18.5: Underweight
• 18.5 - 24.9: Normal weight
• 25.0 - 29.9: Overweight
• 30.0 - 34.9: Obesity Class I
• 35.0 - 39.9: Obesity Class II
• 40.0 and above: Obesity Class III

Understanding Your BMI Results

Underweight (BMI below 18.5)

Being underweight may indicate malnutrition, an eating disorder, or other health problems. If you're underweight, consider consulting a healthcare professional to determine the cause and develop a healthy weight gain plan.

Health risks associated with being underweight include:

• Nutritional deficiencies and compromised immune function
• Hormonal imbalances and reproductive issues
• Bone loss and increased risk of osteoporosis
• Anemia and fatigue
• Delayed wound healing

If you're underweight, focus on nutrient-dense foods that provide healthy calories, protein, and essential nutrients. Consider working with a registered dietitian to develop a personalized nutrition plan.

Normal Weight (BMI 18.5 - 24.9)

A BMI in this range is associated with the lowest health risks. Maintain your healthy weight through balanced nutrition and regular physical activity.

To maintain a healthy weight:

• Eat a balanced diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats
• Stay physically active with at least 150 minutes of moderate-intensity exercise per week
• Get adequate sleep (7-9 hours for adults)
• Manage stress through relaxation techniques, mindfulness, or other stress-reduction strategies
• Stay hydrated by drinking plenty of water throughout the day

Regular health check-ups can help ensure you're maintaining optimal health even with a normal BMI.

Overweight (BMI 25.0 - 29.9)

Being overweight increases your risk of developing health problems such as heart disease, high blood pressure, and type 2 diabetes. Consider making lifestyle changes to achieve a healthier weight.

Health risks associated with being overweight include:

• Hypertension (high blood pressure)
• Dyslipidemia (high LDL cholesterol, low HDL cholesterol, or high triglycerides)
• Type 2 diabetes or prediabetes
• Coronary heart disease
• Stroke
• Gallbladder disease
• Sleep apnea and respiratory problems
• Certain types of cancer

Even modest weight loss (5-10% of your current weight) can significantly reduce these health risks. Focus on sustainable lifestyle changes rather than quick fixes or fad diets.

Obesity (BMI 30.0 and above)

Obesity significantly increases your risk of serious health problems, including heart disease, stroke, type 2 diabetes, certain cancers, and more. If your BMI falls in this range, consider consulting a healthcare professional for personalized advice on weight management.

Obesity is further classified into three categories:

• Class I Obesity (BMI 30.0-34.9): Moderate risk of health problems
• Class II Obesity (BMI 35.0-39.9): High risk of health problems
• Class III Obesity (BMI ≥40.0): Very high risk of health problems

Treatment approaches for obesity may include:

• Comprehensive lifestyle modifications (diet, physical activity, behavior therapy)
• Medically supervised weight loss programs
• Prescription weight-loss medications (for eligible individuals)
• Bariatric surgery (for severe obesity or obesity with significant health complications)

Working with a healthcare team that may include a physician, registered dietitian, exercise specialist, and behavioral therapist can provide the support needed for successful weight management.

Frequently Asked Questions