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BMI Calculator

Calculate your Body Mass Index instantly and discover your healthy weight range. Understand your BMI category and get personalized recommendations for your health journey.

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BMI Calculator

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70 kg
170 cm
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💡 Improving Your BMI

Practical steps toward a healthy weight.

Focus on Body Composition

BMI doesn't distinguish fat from muscle. Two people can have the same BMI with very different health profiles. Pair your BMI score with body fat percentage and waist circumference for the full picture.

Small Deficits Win

A 300–500 kcal daily deficit leads to 0.3–0.5 kg of fat loss per week — sustainable and muscle-preserving. Crash diets cause muscle loss and metabolic slowdown, making long-term BMI improvement harder.

Strength Training Matters

Resistance training builds muscle (which may raise BMI slightly) while dramatically improving metabolic health, body composition, and the risk factors that BMI attempts to predict.

What Does Your BMI Mean?

Body Mass Index (BMI) is a simple numerical measure derived from height and weight. Developed by Belgian mathematician Adolphe Quetelet in the 19th century, it was designed as a population-level statistical tool — not an individual diagnostic. Nevertheless, it remains the most widely used screening metric in clinical practice due to its simplicity and correlation with health risk at population scale.

Research consistently shows that BMI outside the normal range (18.5–24.9) correlates with increased risk of type 2 diabetes, cardiovascular disease, certain cancers, sleep apnea, and joint problems. However, BMI's limitations — particularly its inability to account for muscle mass, ethnicity, age, and fat distribution — mean it should be interpreted alongside other markers.

  • Underweight (<18.5): Risk of nutrient deficiencies, osteoporosis, immune suppression
  • Normal (18.5–24.9): Associated with lowest risk of weight-related disease
  • Overweight (25–29.9): Moderately elevated risk, especially with central obesity
  • Obese (≥30): Significantly elevated risk across multiple health conditions

❓ Frequently Asked Questions

Your BMI questions answered.

A BMI of 18.5–24.9 is considered normal/healthy for most adults. Under 18.5 is underweight, 25–29.9 is overweight, and 30+ is classified as obese. Different thresholds apply for certain Asian populations.

BMI is a useful screening tool but has limitations. It doesn't account for muscle mass, age, sex, or fat distribution. A muscular athlete can have an "overweight" BMI. Always interpret BMI alongside other health markers.

BMI = weight (kg) ÷ height² (m²). For imperial: BMI = 703 × weight (lbs) ÷ height² (inches²). For example, a person weighing 70 kg at 170 cm has a BMI of 70 ÷ (1.70²) = 24.2.

Reduce caloric intake by 300–500 kcal/day below your TDEE, increase physical activity (especially cardio and resistance training), improve sleep quality, and manage stress. Target 0.5 kg/week of fat loss for sustainable BMI improvement.

The healthy BMI range of 18.5–24.9 translates to: a 160 cm person should weigh 47–64 kg; a 170 cm person should weigh 53–72 kg; a 180 cm person should weigh 60–81 kg. Your calculator shows your specific range.

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