⚠️ Disclaimer: This BMI calculator is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. BMI has limitations and may not be accurate for athletes, the elderly, children, or certain ethnic groups. Always consult a qualified healthcare provider for health concerns.
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Key Features
Everything you need, right at your fingertips. Simple, fast, and built for everyone.
Metric & Imperial
Calculate BMI using kg/cm or lb/ft/in —your choice.
Category Breakdown
See where you fall: Underweight, Normal, Overweight, or Obese.
Healthy Range
View the healthy weight range for your specific height.
Instant Calculation
No button press needed —result appears as you type.
Clear Explanations
Understand what BMI means and its limitations.
Clean Interface
No distractions, just a straightforward health check.
How to Use This BMI Calculator
Getting started is easy. Just follow these simple steps.
Choose Units
Select metric (kg/cm) or imperial (lb/ft/in).
Enter Height
Type your height in the appropriate units.
Enter Weight
Type your current weight.
See Your BMI
View your BMI score, category, and healthy weight range.
About This BMI Calculator
Body Mass Index (BMI) is a simple calculation using height and weight that provides a quick screening tool to categorize weight status. It is one of the most widely used metrics in public health and medicine for assessing population-level weight-related health risks.
BMI is calculated by dividing weight in kilograms by height in meters squared (kg/m2). For imperial measurements, the formula is weight in pounds times 703 divided by height in inches squared. The result falls into categories: underweight (below 18.5), normal (18.5-24.9), overweight (25-29.9), and obese (30+).
While BMI is useful for population studies and initial screening, it has important limitations. It does not distinguish between muscle and fat, so athletes and very muscular individuals may fall into the overweight or obese categories despite having low body fat percentages. It also does not account for age, gender, ethnicity, or body fat distribution.
For a comprehensive assessment of your health and weight status, consider multiple factors beyond BMI including waist circumference, body composition, blood pressure, cholesterol levels, family history, and overall fitness level. Always consult a healthcare professional for personalized health advice and diagnosis.
Frequently Asked Questions
What is BMI?
BMI (Body Mass Index) is a simple calculation using a person's height and weight. The formula is BMI = weight (kg) / height² (m²), or BMI = weight (lbs) / height² (in²) × 703. BMI is used as a screening tool to identify possible weight categories that may lead to health problems.
What is a healthy BMI range?
For adults, a BMI below 18.5 is considered underweight, 18.5-24.9 is normal weight, 25-29.9 is overweight, and 30 or above is obese. However, BMI is a screening tool and not a diagnostic measure of body fat or health.
Is BMI accurate for everyone?
BMI has limitations. It may overestimate body fat in athletes and people with a muscular build, and it may underestimate body fat in older people or those who have lost muscle mass. It also doesn't account for age, gender, ethnicity, or body composition. Always consult a healthcare provider for a complete assessment.
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered normal weight. Below 18.5 is underweight, 25-29.9 is overweight, and 30 or above is obese. However, BMI does not account for muscle mass, bone density, age, and other factors, so it should be used as a general guideline rather than a definitive measure.
How many calories should I eat per day?
Daily calorie needs depend on age, gender, weight, height, activity level, and goals. An average sedentary adult needs about 1800-2200 calories for women and 2200-2600 for men. To lose weight, aim for a moderate deficit of 300-500 calories below maintenance.
How accurate is BMI for athletes?
BMI is less accurate for athletes and bodybuilders because muscle is denser than fat. A muscular person with low body fat can have a BMI in the overweight or obese range. For athletes, body fat percentage, waist circumference, and overall fitness level are better health indicators.
What is BMR and how is it calculated?
BMR (Basal Metabolic Rate) is the number of calories you burn at rest. The Mifflin-St Jeor equation is the most accurate: for men BMR = 10*weight(kg) + 6.25*height(cm) - 5*age + 5, for women BMR = 10*weight(kg) + 6.25*height(cm) - 5*age - 161.
How do I lose weight safely?
Safe weight loss is 0.5-1 kg (1-2 lbs) per week through a combination of moderate calorie deficit, balanced nutrition, and regular physical activity. Extreme diets can cause muscle loss, nutrient deficiencies, and rebound weight gain. Consult a healthcare provider before starting any weight loss plan.
Does muscle really weigh more than fat?
A kilogram of muscle weighs the same as a kilogram of fat, but muscle is much denser and takes up less volume. This is why two people of the same height and weight can look very different depending on their body composition. Strength training can change your body shape without changing the scale number.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day, including BMR plus activity from exercise, movement, and digestion. It is calculated by multiplying your BMR by an activity factor (1.2 for sedentary, up to 1.9 for very active).
How does sleep affect weight?
Poor sleep disrupts hunger hormones (ghrelin and leptin), increases cravings for high-calorie foods, lowers metabolism, and reduces motivation to exercise. Getting 7-9 hours of quality sleep is an important factor in maintaining a healthy weight and overall health.
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered normal weight. Below 18.5 is underweight, 25-29.9 is overweight, and 30 or above is obese. However, BMI does not account for muscle mass, bone density, age, and other factors, so it should be used as a general guideline rather than a definitive measure.
How many calories should I eat per day?
Daily calorie needs depend on age, gender, weight, height, activity level, and goals. An average sedentary adult needs about 1800-2200 calories for women and 2200-2600 for men. To lose weight, aim for a moderate deficit of 300-500 calories below maintenance.
How accurate is BMI for athletes?
BMI is less accurate for athletes and bodybuilders because muscle is denser than fat. A muscular person with low body fat can have a BMI in the overweight or obese range. For athletes, body fat percentage, waist circumference, and overall fitness level are better health indicators.
What is BMR and how is it calculated?
BMR (Basal Metabolic Rate) is the number of calories you burn at rest. The Mifflin-St Jeor equation is the most accurate: for men BMR = 10*weight(kg) + 6.25*height(cm) - 5*age + 5, for women BMR = 10*weight(kg) + 6.25*height(cm) - 5*age - 161.
How do I lose weight safely?
Safe weight loss is 0.5-1 kg (1-2 lbs) per week through a combination of moderate calorie deficit, balanced nutrition, and regular physical activity. Extreme diets can cause muscle loss, nutrient deficiencies, and rebound weight gain. Consult a healthcare provider before starting any weight loss plan.
Does muscle really weigh more than fat?
A kilogram of muscle weighs the same as a kilogram of fat, but muscle is much denser and takes up less volume. This is why two people of the same height and weight can look very different depending on their body composition. Strength training can change your body shape without changing the scale number.
What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories you burn in a day, including BMR plus activity from exercise, movement, and digestion. It is calculated by multiplying your BMR by an activity factor (1.2 for sedentary, up to 1.9 for very active).
How does sleep affect weight?
Poor sleep disrupts hunger hormones (ghrelin and leptin), increases cravings for high-calorie foods, lowers metabolism, and reduces motivation to exercise. Getting 7-9 hours of quality sleep is an important factor in maintaining a healthy weight and overall health.
Understanding Health and Fitness Metrics
Maintaining good health involves understanding various metrics and how they relate to your overall well-being. Body Mass Index, daily calorie needs, heart rate, and body composition are all pieces of the puzzle, but no single number tells the whole story of your health.
Body Mass Index (BMI) is a widely used screening tool that categorizes weight status, but it has important limitations. BMI does not distinguish between muscle and fat, so athletes and very muscular people may be classified as overweight despite being healthy. It is best used as a starting point rather than a definitive diagnosis.
Calorie needs vary dramatically from person to person. A person's age, gender, height, weight, body composition, genetics, and activity level all play a role. The most sustainable approach to managing weight is focusing on nutrient-dense foods, regular physical activity, and building long-term healthy habits rather than short-term diets.
Sleep, stress management, and mental health are often overlooked factors that strongly impact physical health. Chronic stress raises cortisol levels, which can lead to weight gain, weakened immunity, and increased risk of various health conditions. Getting 7-9 hours of quality sleep each night is foundational to every aspect of health.
Remember that health is a journey, not a destination. Small, consistent improvements in your daily habits, done over months and years, lead to the biggest results. Be patient with yourself, celebrate non-scale victories like more energy and better sleep, and always consult healthcare professionals for personalized advice.