BMI Calculator
Calculate your Body Mass Index instantly in either metric (kg, cm) or imperial (lb, ft/in) units. See your BMI score along with the standard weight category and the healthy weight range for your height.
How to use the BMI Calculator
Select metric or imperial units, enter your height and weight, and your BMI is calculated immediately. The result includes your numeric BMI value and the corresponding WHO weight category (Underweight, Normal weight, Overweight, or Obese).
How BMI is calculated
Metric: BMI = Weight (kg) ÷ Height (m)2.
Imperial: BMI = (Weight (lb) ÷ Height (in)2) × 703.
BMI categories (WHO): Underweight < 18.5 • Normal weight 18.5–24.9 • Overweight 25–29.9 • Obese ≥ 30.
Frequently Asked Questions
What is a healthy BMI?
According to the World Health Organization, a BMI between 18.5 and 24.9 is considered the normal (healthy) weight range for adults. Values below 18.5 indicate underweight, 25–29.9 indicates overweight, and 30 or above indicates obesity.
Is BMI accurate for everyone?
BMI is a useful population-level screening tool but has well-known limitations. It does not distinguish between muscle and fat, so a muscular athlete may be classified as overweight. It also does not account for age, sex, ethnicity, or where fat is distributed in the body.
What is the healthy weight range for my height?
The calculator shows your healthy weight range directly below the BMI result. This is the weight span that produces a BMI between 18.5 and 24.9 for your entered height.
How do I convert between metric and imperial?
Use the toggle at the top of the calculator to switch between metric (kg, cm) and imperial (lb, ft/in). The tool switches the input fields; you do not need to convert values yourself.
Does BMI apply to children?
This calculator uses adult BMI thresholds. For children and teenagers (ages 2–19), BMI is interpreted differently using age- and sex-specific percentile charts. Consult a paediatrician for children's BMI assessment.