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BMI Calculator

Calculate your Body Mass Index (BMI) using metric (kg/cm) or imperial (lb/in) units. BMI categories: Underweight < 18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese ≥ 30.

kg
cm
lb
in

Fill in the fields above and click Calculate to see your results.

How to use

Calculate your Body Mass Index (BMI) using metric (kg/cm) or imperial (lb/in) units. BMI categories: Underweight < 18.5, Normal 18.5–24.9, Overweight 25–29.9, Obese ≥ 30.

How it's calculated

BMI (Metric)

weight_kg / pow(height_cm / 100, 2)

BMI calculated from kg and cm

BMI (Imperial)

703 * weight_lb / pow(height_in, 2)

BMI calculated from lb and inches

Your BMI

(unit_system == 1) * bmi_metric + (unit_system == 2) * bmi_imperial

BMI < 18.5: Underweight | 18.5–24.9: Normal | 25–29.9: Overweight | ≥ 30: Obese

Examples

Average adult: 70 kg, 170 cm

  • Height (cm):170
  • Height (inches):67
  • Weight (kg):70
  • Weight (lb):154
  • Unit System:1

Slightly overweight: 80 kg, 175 cm

  • Height (cm):175
  • Height (inches):69
  • Weight (kg):80
  • Weight (lb):176
  • Unit System:1

Frequently Asked Questions

What is BMI and what do the numbers mean?

BMI (Body Mass Index) is a number calculated from your weight and height. Categories: Underweight (< 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), Obese (≥ 30). It is a screening tool, not a diagnostic measure.

Is BMI accurate for everyone?

BMI has limitations. It does not account for muscle mass, bone density, age, or fat distribution. Athletes may have a high BMI due to muscle, while older adults may have a normal BMI but excess body fat. Always consult a healthcare professional for a full assessment.

What is a healthy BMI for Vietnamese adults?

The World Health Organization uses 18.5–24.9 as the normal range globally. However, some Asian health guidelines suggest a lower overweight threshold of 23.0 due to differences in body composition. Consult your doctor for personalised advice.

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