BMI Calculator

Calculate your Body Mass Index (BMI) to understand your weight category.

Enter Your Details

Height (ft)

Height (in)

Weight (lbs)

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Your BMI:

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How to Use the BMI Calculator

Select your preferred units (Imperial or Metric).

Enter your height and weight in the corresponding fields.

Click "Calculate BMI" to see your result and category.

Use the gauge chart to visualize where your BMI falls.

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Help your users check their BMI by embedding this calculator.

Frequently Asked Questions

What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It's used as a screening tool to identify potential weight problems.

What are the BMI categories?

Generally, BMI categories are: Underweight (below 18.5), Normal weight (18.5â€"24.9), Overweight (25â€"29.9), Obesity Class I (30â€"34.9), Obesity Class II (35â€"39.9), Obesity Class III (40 or higher).

Is BMI always accurate?

BMI is a useful screening tool but doesn't directly measure body fat. It may overestimate body fat in athletes or those with muscular builds, or underestimate it in older persons or those who have lost muscle mass. It shouldn't be the sole indicator of health.

Should I be concerned about my BMI?

If your BMI falls outside the 'Normal weight' range, it's a good idea to discuss it with a healthcare provider. They can assess your individual health status, considering factors like muscle mass, waist circumference, and overall health history.

Learn More About Body Mass Index (BMI)

1. Introduction: What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/mÂ², where kg is a person's weight in kilograms and mÂ² is their height in meters squared. For adults 20 years old and older, BMI is interpreted using standard weight status categories that are the same for all ages and for both men and women. It's a widely used screening tool to identify potential weight problems, but it does not diagnose body fatness or the health of an individual.

2. How the Calculator Works: The BMI Formula

The calculator takes your height and weight as input, either in metric (cm, kg) or imperial (ft, in, lbs) units.

If Metric: BMI = Weight (kg) / [Height (m)]^2 (Height in cm is converted to meters by dividing by 100).
If Imperial: BMI = [Weight (lbs) / (Height (in))^2] * 703 (Height in feet and inches is converted to total inches).

The calculated BMI value is then compared to standard weight status categories:

Below 18.5: Underweight
18.5 â€" 24.9: Normal or Healthy Weight
25.0 â€" 29.9: Overweight
30.0 and Above: Obesity (often further divided into classes)

The calculator displays your BMI score, the corresponding category, and a visual representation on a standard BMI chart.

3. Why It Matters / Benefits: A Quick Screening Tool

BMI is a useful population-level measure of overweight and obesity. For individuals, it can be a helpful screening tool because:

It's Simple & Inexpensive: Requires only height and weight measurements.
Identifies Potential Risk: Higher BMI is associated with increased risk for certain diseases like heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.
Provides a Starting Point: Can prompt individuals to discuss their weight and overall health with a healthcare provider.

However, it's crucial to understand its limitations.

4. Limitations of BMI

Doesn't Distinguish Fat from Muscle: BMI may overestimate body fat in athletes and others with muscular builds, potentially categorizing them as 'Overweight' despite being healthy.
Doesn't Account for Body Composition: It may underestimate body fat in older persons and others who have lost muscle mass. See our Body Fat Percentage Calculator for an alternative perspective.
Doesn't Consider Fat Distribution: Where fat is stored (e.g., abdominal fat) can be more indicative of health risk than total fat alone. Waist circumference is another useful measure.
Not for Children/Teens: BMI interpretation differs for those under 20. Use the BMI Percentile Calculator for children and teens.
Not for Pregnant Women: BMI is not applicable during pregnancy. See the Pregnancy Weight Gain Calculator.
Screening, Not Diagnosis: A high BMI indicates potential risk, but doesn't diagnose health. A healthcare provider performs further assessments (diet, physical activity, family history, other health screenings) to evaluate risk and health status.

5. Expert Tips / Best Practices

Use as a Starting Point: Treat your BMI result as one piece of information about your health, not the definitive answer.
Measure Accurately: Ensure your height and weight measurements are reasonably accurate for a reliable calculation.
Consider Trends: Tracking your BMI over time can be more informative than a single measurement.
Focus on Healthy Habits: Regardless of BMI, prioritize a balanced diet, regular physical activity, adequate sleep, and stress management for overall health. Use tools like the Calorie Needs and Macro Split calculators to help plan your diet.
Consult Your Doctor: Discuss your BMI result and any concerns about your weight or health with a healthcare professional. They can provide personalized advice and recommend further assessments if needed.

6. Conclusion: A Useful, But Limited, Indicator

The BMI Calculator provides a quick and easy way to screen for potential weight-related health risks based on your height and weight. While it has limitations and shouldn't be used as the sole measure of health, it remains a valuable tool for population studies and as an initial indicator for individuals. Understanding your BMI category can be the first step towards a conversation with your doctor about maintaining a healthy weight and lifestyle.