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How to Use BMI Calculator
Step 1
Enter height
Step 2
Enter weight
Step 3
View your BMI
Step 4
Check BMI range
What Is BMI?
BMI (Body Mass Index) is a numerical value calculated from your height and weight that provides a general indication of whether you have a healthy body weight for your height. It is widely used by health professionals as a screening tool — not a diagnostic measure — to identify potential weight-related health risks.
How to Calculate Your BMI Online
- Enter your height in centimeters or feet and inches.
- Enter your weight in kilograms or pounds.
- View your BMI score — calculated instantly.
- Check your BMI range to see which category your result falls into.
BMI Formula
Metric: BMI = weight (kg) ÷ height² (m²)
Imperial: BMI = (weight (lbs) × 703) ÷ height² (inches²)
For example, a person who is 175cm tall and weighs 70kg has a BMI of 70 ÷ (1.75²) = 22.9.
BMI Categories
Under 18.5: Underweight — may indicate nutritional deficiency or other health issues.
18.5 – 24.9: Normal weight — associated with lower risk of weight-related health problems.
25.0 – 29.9: Overweight — may increase risk of cardiovascular disease and type 2 diabetes.
30.0 and above: Obese — associated with significantly higher health risks.
Limitations of BMI
BMI is a screening tool, not a complete health assessment. It does not account for muscle mass — athletes often have a high BMI despite low body fat. It does not differentiate between fat distribution (abdominal fat is riskier than fat elsewhere). It also doesn’t account for age, sex, or ethnicity differences. Always consult a healthcare professional for a full health assessment.
Frequently Asked Questions
Is BMI the same for men and women? The formula is the same, but health interpretations can differ. Body composition differs between sexes, and some health organizations use adjusted BMI ranges.
What is a healthy BMI for adults? The World Health Organization considers 18.5 to 24.9 the normal range for adults.
Should children use the same BMI scale? No — children use age- and sex-specific BMI percentiles, not the adult categories above.