⚖️ BMI Calculator
Check your Body Mass Index against the World Health Organization (WHO) categories.
How to use the BMI Calculator
Enter your height in centimeters or feet and your weight to get your BMI, shown against both the WHO classification and the Asian cut-offs used across much of Asia.
How it works
BMI is weight in kg ÷ height in metres squared. The WHO thresholds and the Asian cut-offs disagree at the boundary: a BMI of 23.5 is "normal" under WHO rules but "overweight" under Asian guidelines, because populations at the same BMI carry more visceral fat at lower values. Showing both avoids a misleading single verdict.
When to use it
Use it to sanity-check a number from a clinic visit, to compare readings over time, and to understand why two people with identical BMI can have very different body composition.
Worked example
For a 175 cm, 70 kg adult:
| Standard | BMI | Category |
|---|---|---|
| Calculation | 70 ÷ 1.75² = 22.86 | — |
| WHO | 22.86 | Normal (18.5–24.9) |
| Asian cut-off | 22.86 | Normal (18.5–23.9) |
Assumptions and limitations
BMI cannot distinguish muscle from fat, so an athlete and a sedentary person at the same BMI may be in very different states of health. It is not valid for children, the elderly or pregnancy. Waist circumference and body fat percentage are more informative for metabolic risk. This tool is not medical advice.
Frequently Asked Questions
What is a healthy BMI?
The WHO classifies 18.5–24.9 as normal weight, below 18.5 as underweight, 25–29.9 as overweight and 30+ as obesity. BMI is a screening tool, not a diagnosis.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so very muscular people often score "overweight" despite low body fat. Body composition measures like skinfold or DEXA are better for athletes.
Is BMI different for men and women?
The formula is the same for adult men and women, but body composition typically differs. For children and teens, age- and sex-specific percentile charts are used instead.
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