BMI Calculator
Enter height and weight to compute BMI and get the weight category and health advice per WHO / Asian standards.
Input Data
Results
At a glance:BMI = weight(kg) ÷ height(m)². WHO international cut-offs: <18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, ≥30 obese. Asian / Hong Kong cut-offs are stricter: <18.5 underweight, 18.5–22.9 normal, 23–24.9 overweight, ≥25 obese. This tool uses the Asian standard.
Formula
Height(m) = height(cm) ÷ 100.
BMI = weight(kg) ÷ height(m)².
Asian standard: <18.5 underweight / 18.5–22.9 normal / 23–24.9 overweight / ≥25 obese.
How to Use
- Enter your height in centimetres.
- Enter your weight in kilograms.
- The tool shows your BMI and category.
Case Studies
170cm / 65kg
Height 1.7m → BMI = 65 ÷ 1.7² = 65 ÷ 2.89 = 22.5.
Falls in the 'normal' range (Asian standard 18.5–22.9).
FAQ
What does BMI mean?
BMI (Body Mass Index) is a common screening measure that uses height and weight to estimate body fat and health risk. A higher value generally means more weight relative to height.
How do WHO and Asian standards differ?
At the same BMI, Asians (including Hong Kong) tend to carry more body fat and metabolic risk, so stricter cut-offs are used: overweight from 23 and obese from 25 (vs WHO's 25 and 30). This tool uses the Asian standard.
Is BMI accurate? Do athletes skew it?
BMI does not distinguish muscle from fat. Muscular people (e.g. gym-goers) may show a high BMI yet low body fat and be misclassified as 'overweight'. It is only a screening tool and should be combined with body-fat percentage, waist circumference and other measures.
Does it apply to children and the elderly?
Children and teens use age-specific BMI percentile charts; the elderly, with muscle loss, may have a slightly higher BMI (e.g. 22–27) that correlates with lower mortality. The adult standard here should not be applied directly.
Can I use it during pregnancy or illness?
Pregnancy, oedema or acute illness temporarily change weight, so BMI is not meaningful in those periods — retest after delivery or recovery.
Does a normal BMI mean I'm healthy?
Not necessarily. A normal BMI with high body fat ('skinny fat') or a large waist still carries elevated metabolic risk. Regular exercise, balanced diet and waist management matter too.
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References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.