BMI Calculator

Calculate your Body Mass Index (BMI) to see where you fall on the weight scale for your height.

BMI Calculator

Your BMI Results

24.2

Normal

Body Mass Index

For your height of 5'7", a healthy weight range is:

118 - 159 lb

24.2BMI

BMI Categories

Underweight

BMI: < 18.5

Normal

BMI: 18.5 - 24.9

Overweight

BMI: 25 - 29.9

Obese Class I

BMI: 30 - 34.9

Obese Class II

BMI: 35 - 39.9

Obese Class III

BMI: ≥ 40

Health Implications

Normal Weight (BMI 18.5-24.9)

Maintaining a healthy weight reduces your risk of various health conditions. Focus on:

  • Regular physical activity (150+ minutes per week)
  • Balanced, nutritious diet
  • Regular health check-ups
  • Adequate sleep
  • Stress management

Continue your healthy lifestyle habits to maintain this weight range.

Note: BMI is a screening tool, not a diagnostic tool. It does not directly measure body fat or account for factors like muscle mass, bone density, or body composition. Always consult healthcare professionals for personalized health advice.

Understanding BMI

BMI is just a ratio of your weight to your height. It's a quick screening tool that gives you a general idea of whether you're underweight, normal weight, overweight, or obese. It's not perfect, but it's a useful starting point.

How BMI Is Calculated

BMI is calculated using the following formula:

For metric measurements:

BMI = weight (kg) / [height (m)]²

For imperial measurements:

BMI = [weight (lb) / height (in)²] × 703

BMI Categories and What They Mean

BMI values are categorized into ranges, each associated with different health implications:

  • Underweight (BMI below 18.5): May indicate malnutrition, an eating disorder, or other health problems.
  • Normal weight (BMI 18.5-24.9): Associated with the lowest health risks for most people.
  • Overweight (BMI 25-29.9): May increase the risk of health problems, particularly if accompanied by other risk factors.
  • Obesity Class I (BMI 30-34.9): Associated with a higher risk of health issues like heart disease and diabetes.
  • Obesity Class II (BMI 35-39.9): Significantly increased health risks.
  • Obesity Class III (BMI 40 or higher): Severely increases the risk of health problems and mortality.

Limitations of BMI

While BMI is a useful screening tool, it has several important limitations to keep in mind:

Muscle Mass

BMI doesn't distinguish between muscle and fat. Highly muscular individuals (like athletes) may have a high BMI despite having little body fat.

Body Composition

Two people with the same BMI can have very different body compositions and fat distributions, which affect health risks differently.

Age Considerations

BMI may be less accurate in elderly populations due to natural changes in body composition with aging, including loss of muscle mass.

Ethnic Variations

BMI thresholds may not be appropriate for all ethnic groups. For example, Asian populations may face higher health risks at lower BMI values.

Strategies for Maintaining a Healthy Weight

Whether you're looking to lose weight, gain weight, or maintain your current weight, these evidence-based strategies can help you achieve your goals:

Weight Management Approaches

For Weight Loss

  • Create a calorie deficit: Consume fewer calories than you burn
  • Focus on nutrition: Prioritize nutrient-dense foods
  • Increase physical activity: Aim for 150+ minutes of exercise weekly
  • Monitor portion sizes: Use smaller plates and read food labels
  • Stay hydrated: Drink water before meals and minimize sugary beverages

For Weight Gain

  • Create a calorie surplus: Consume more calories than you burn
  • Focus on nutrient-dense foods: Choose foods high in healthy fats and proteins
  • Eat more frequently: Have 5-6 smaller meals throughout the day
  • Incorporate strength training: Build muscle mass through resistance exercise
  • Choose calorie-rich, nutritious foods: Nuts, avocados, whole milk dairy

Evidence-Based Approaches

Research shows that certain approaches to weight management are more effective for long-term success:

Recommended Practices

  • Regular self-monitoring of weight and habits
  • Mindful eating (paying attention to hunger cues)
  • Consistent physical activity routines
  • Adequate sleep (7-9 hours nightly)
  • Social support and accountability
  • Focus on sustainable lifestyle changes

Practices to Avoid

  • Extremely restrictive diets
  • "All-or-nothing" thinking
  • Relying on supplements instead of whole foods
  • Skipping meals regularly
  • Using exercise to "earn" food
  • Ignoring emotional aspects of eating

Common Mistakes

Using BMI as your only health metric: BMI doesn't tell you anything about body composition. A muscular person can have a high BMI but low body fat. Someone with a normal BMI can still have too much visceral fat. Use it with other measures like waist circumference and how you actually feel.

Ignoring that standards vary: Asian populations face higher health risks at lower BMIs. Older adults might be healthier at slightly higher BMIs. One size doesn't fit all.

Measuring incorrectly: Weigh yourself naked in the morning after using the bathroom. Measure height without shoes. Use the same scale each time. Small measurement errors can throw off your BMI.

Checking it too often: Your weight fluctuates 2-5 pounds daily just from water, food, and hormones. Checking your BMI every day and freaking out about small changes isn't helpful. Look at monthly trends instead.

A Word About BMI Limitations

BMI is a helpful screening tool, but it's not the whole picture. It doesn't tell you anything about your actual body composition—whether you're carrying muscle or fat. It also doesn't account for where you carry weight, which matters for health risks. Use it as one data point among others like waist circumference, how you feel, and your overall health markers. The number matters less than the trend and your overall wellness.

Frequently Asked Questions

How accurate is BMI?

BMI is a decent screening tool, but it has real limitations. It can't tell the difference between muscle and fat, and it doesn't account for things like bone density or where you carry your weight. Use it as one piece of information, not the whole story.

Can my BMI be "normal" but still be unhealthy?

Yes. People with a normal BMI can still have unhealthy levels of visceral fat (fat around organs), poor cardiovascular fitness, or metabolic issues. This is sometimes called "normal weight obesity" or being "skinny fat." Conversely, some individuals with an "overweight" BMI may be metabolically healthy, especially if they're physically active and have good muscle mass.

How often should I check my BMI?

Every 3-6 months is plenty for most people. If you're actively working on changing your weight, maybe monthly. But don't obsess over it—healthy weight changes take time, and your BMI shouldn't fluctuate much week to week anyway.

Are BMI categories the same for children and adults?

No. For children and teens, BMI is age- and sex-specific and is often referred to as "BMI-for-age." Instead of fixed categories, children's BMI is compared to percentiles for children of the same age and sex. This calculator is designed for adults aged 20 and older.

What are alternatives to BMI for assessing health?

Several other measurements can complement BMI: waist circumference, waist-to-hip ratio, body fat percentage (via skinfold measurements, bioelectrical impedance, DEXA scans), blood pressure, cholesterol levels, blood glucose levels, and cardiorespiratory fitness assessments.

Can BMI be used for athletes and very muscular people?

BMI is not ideal for athletes and highly muscular individuals because it doesn't differentiate between muscle and fat mass. A bodybuilder or NFL player might have a BMI of 28-30 (classified as overweight/obese) while having very low body fat. For these populations, body fat percentage, waist circumference, and performance metrics are more meaningful health indicators.

What BMI range is considered healthy?

For most adults, a BMI between 18.5 and 24.9 is considered healthy. However, this range may vary based on age, ethnicity, and individual factors. Asian populations may have lower healthy ranges (18.5-22.9), while older adults might have slightly higher optimal ranges (25-27). Always consider BMI alongside other health markers and consult healthcare providers for personalized guidance.

Does BMI account for age-related changes in body composition?

No, BMI doesn't account for age-related changes like muscle loss (sarcopenia) or changes in bone density. As we age, we naturally lose muscle mass and may experience changes in fat distribution. For adults over 65, slightly higher BMI values (25-27) might be protective against fractures and mortality. This is why healthcare providers often interpret BMI differently for older adults.

Can medication affect BMI or weight?

Yes, many medications can affect weight and therefore BMI. Antidepressants, antipsychotics, diabetes medications, corticosteroids, and birth control can cause weight gain. Blood pressure medications and some antidepressants might cause weight loss. If you notice significant weight changes after starting a new medication, discuss this with your healthcare provider. They may adjust dosages or suggest alternatives.

How does BMI relate to disease risk?

BMI is associated with increased risk of several diseases. Higher BMI increases risk of type 2 diabetes, heart disease, stroke, sleep apnea, certain cancers, and osteoarthritis. However, BMI alone doesn't determine disease risk - waist circumference, fitness level, family history, and other factors are equally important. Some people with higher BMI may be metabolically healthy, while others with normal BMI may have health issues.

Is it possible to have a healthy BMI but still be at risk for health problems?

Yes, this condition is sometimes called "normal weight obesity" or being "metabolically obese, normal weight." People with normal BMI can have high visceral fat, insulin resistance, poor cardiovascular fitness, or other metabolic issues. This is why waist circumference, blood markers, and fitness levels are important health indicators beyond BMI. Regular health screenings help identify these risks.

What's the difference between BMI and body fat percentage?

BMI is a ratio of weight to height that doesn't distinguish between muscle, fat, bone, and other tissues. Body fat percentage measures the proportion of fat mass to total body weight. A healthy body fat percentage is typically 10-22% for men and 20-32% for women, varying with age. Body fat percentage is more accurate for assessing health risks, especially for athletes or those with high muscle mass.

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Disclaimer: This BMI calculator is provided for informational purposes only and is not a substitute for professional medical advice. BMI has limitations and may not be suitable for all individuals, including pregnant women, athletes, and the elderly. Always consult with healthcare professionals for personalized health assessments and advice.