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BMI Calculator

Body Mass Index (BMI) is a simple measure of body fat based on your height and weight. It applies to adult men and women and is used by healthcare professionals worldwide as a quick screening tool for weight categories that may lead to health problems.

Quick Answer

A healthy BMI is 18.5–24.9. Calculate yours by dividing your weight in kilograms by your height in meters squared.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

Enter your weight and height above to calculate your BMI.

How the Formula Works

  1. Measure your weight in kilograms. If using pounds, convert by multiplying by 0.453592.

    weight (kg) = weight (lbs) × 0.453592

  2. Measure your height in meters. If using feet and inches, convert to meters first.

    height (m) = (feet × 12 + inches) × 0.0254

  3. Square your height by multiplying it by itself.

    height² = height (m) × height (m)

  4. Divide your weight in kilograms by your squared height in meters to get your BMI.

    BMI = weight (kg) ÷ height (m)²

Methodology & Sources

Reviewed and updated March 28, 2026 · Prepared by GetHealthyCalculators Editorial Team

This calculator uses the standard adult BMI equation and WHO classification bands. It is designed as a screening tool, not a diagnostic assessment of body composition or health status.

References

  • Body Mass Index (BMI) · Centers for Disease Control and Prevention
  • BMI classification · World Health Organization

How to Interpret Your Results

BMI values are grouped into categories defined by the World Health Organization (WHO). These categories help identify potential weight-related health risks. Keep in mind that BMI is a screening tool and does not directly measure body fat percentage or overall health.

Underweight
0–18.4 — Below healthy weight range. Consult a healthcare provider if concerned.
Healthy Weight
18.5–24.9 — Within the healthy weight range for your height.
Overweight
25–29.9 — Above healthy weight range. Consider lifestyle modifications.
Obese (Class I)
30–34.9 — Increased health risks. Consult a healthcare provider.
Obese (Class II)
35–39.9 — Significant health risks. Medical consultation recommended.
Obese (Class III)
40–100 — Severe health risks. Immediate medical consultation recommended.

Limitations

  • BMI does not distinguish between muscle mass and fat. Athletes or muscular individuals may have a high BMI despite low body fat.
  • BMI does not account for bone density, body composition, or overall fitness level.
  • BMI categories may not apply equally to children, elderly individuals, or pregnant women.
  • BMI is a screening tool only and should not be used as a medical diagnosis. Always consult a qualified healthcare provider for personalized assessment.

Frequently Asked Questions

What is BMI and how is it calculated?
BMI (Body Mass Index) is calculated by dividing your weight in kilograms by your height in meters squared. It provides a numerical value that corresponds to weight categories established by the World Health Organization.
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered a healthy weight range for most adults. However, individual health depends on many factors beyond BMI, including muscle mass, diet, activity level, and family history.
Is BMI accurate for athletes and muscular individuals?
BMI may overestimate body fat in athletes and people with high muscle mass, since it cannot distinguish between muscle and fat. If you are highly active or muscular, consider additional assessments like body fat percentage measurement.
Does BMI apply to children and teenagers?
Standard BMI categories are designed for adults aged 20 and older. For children and teens, BMI is calculated the same way but interpreted using age- and sex-specific percentile charts.
What should I do if my BMI is outside the healthy range?
If your BMI is outside the healthy range, consider consulting a healthcare provider or registered dietitian. They can provide personalized recommendations for diet, exercise, and lifestyle changes based on your individual health profile.
Can you have a normal BMI but an unhealthy body fat percentage?
Yes. BMI does not measure fat directly, so someone can fall in the normal BMI range while still carrying excess body fat or having low muscle mass. That is why body fat percentage and waist-to-hip ratio can add useful context.
Does BMI mean the same thing for men and women?
The BMI equation is the same for men and women, but body composition differs by sex. Women naturally carry a higher percentage of essential fat, so BMI should be interpreted alongside other health markers rather than in isolation.

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