May 30, 2026 Submit Article

BMI Calculator

Find out your Body Mass Index and understand what it means for your health. Get personalized diet and exercise tips based on your result.

Calculate Your BMI

Your BMI Result
kg/m²
BMI Scale
Underweight
Normal
Over
Obese
What is BMI?
Body Mass Index (BMI) = weight (kg) ÷ height² (m²). It's a screening tool to categorize weight status: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese (30+).
BMI Limitations
BMI doesn't distinguish between muscle and fat. Athletes may have a high BMI but low body fat. It also doesn't account for age, gender, or fat distribution.
Healthy Range
A BMI of 18.5–24.9 is associated with the lowest risk of heart disease, diabetes, and other weight-related conditions for most adults.
Understanding BMI

BMI Categories & Health Risks

The World Health Organization (WHO) classifies BMI into four main categories for adults aged 20 and older.

Underweight

BMI < 18.5

Being underweight can indicate malnutrition, eating disorders, or underlying health conditions.

  • Weakened immune system
  • Osteoporosis & bone fractures
  • Vitamin deficiencies & anemia
  • Hormonal imbalances
  • Increased mortality risk

Normal Weight

BMI 18.5 – 24.9

This range is associated with the lowest risk of weight-related health problems.

  • Lower risk of heart disease
  • Better blood sugar control
  • Healthy immune function
  • Optimal hormone balance
  • Longer life expectancy

Overweight

BMI 25 – 29.9

Excess weight increases risk of chronic diseases. Lifestyle changes can bring BMI back to normal.

  • High blood pressure
  • Type 2 diabetes
  • Heart disease & stroke
  • Sleep apnea
  • Joint problems & osteoarthritis

Obese

BMI ≥ 30

Obesity significantly raises the risk of serious health conditions. Medical guidance is recommended.

  • Severe heart disease
  • Type 2 diabetes (high risk)
  • Certain cancers
  • Depression & anxiety
  • Significantly reduced life expectancy
Important

Limitations of BMI

BMI is a useful screening tool, but it has important limitations you should know about.

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Doesn't Measure Body Fat Directly

BMI only considers weight and height — it cannot distinguish between muscle, fat, bone, and water. A muscular athlete may have a "high BMI" but low body fat percentage.

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Varies by Age, Sex & Ethnicity

Older adults tend to have more body fat than younger adults at the same BMI. Women naturally carry more fat than men. Asian populations face health risks at lower BMI thresholds (≥23 for overweight, ≥27.5 for obese).

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Doesn't Account for Fat Distribution

Where you carry fat matters. Visceral fat (around the belly) is far more dangerous than subcutaneous fat (under the skin). BMI cannot tell the difference. Consider measuring your waist circumference alongside BMI.

FAQ

Frequently Asked Questions

What is a healthy BMI for adults?

A BMI between 18.5 and 24.9 is considered the healthy range for most adults. This range is associated with the lowest risk of weight-related diseases. However, individual health depends on many factors beyond BMI.

Is BMI accurate for athletes and bodybuilders?

No. BMI doesn't distinguish between muscle and fat. Athletes and bodybuilders often fall into the "overweight" or "obese" BMI categories despite having low body fat. For active individuals, body fat percentage or waist-to-hip ratio may be better indicators.

How is BMI calculated?

BMI is calculated using your weight and height. Our calculator does the math for you — just enter your details and get your result instantly with category and health insights.

Does BMI apply to children and teens?

For children and teens (ages 2–20), BMI is calculated the same way but interpreted differently using age and gender-specific percentile charts from the CDC. A child's BMI percentile shows how they compare to peers of the same age and sex.

How often should I check my BMI?

For most adults, checking BMI every few months is sufficient. If you're actively working on weight management, monthly tracking alongside other metrics (waist circumference, body fat %, fitness level) gives a more complete picture.

Can BMI predict health problems?

BMI is a screening tool, not a diagnostic tool. High BMI increases the statistical risk of certain conditions (diabetes, heart disease), but it cannot predict individual health outcomes. Always consult a healthcare provider for a complete health assessment.