Body mass index in metric or imperial, with your healthy range.
Your BMI
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Healthy weight for your height
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Distance from that range
Where you sit on the scale
BMI is a screening figure, not a diagnosis — it cannot tell muscle from fat, and thresholds differ by age and ethnicity. Talk to a doctor before acting on it.
Measures mass, not body fat — muscular builds are misclassified.
South and East Asian populations: 23 commonly used as the overweight threshold.
Under 18s need age-and-sex percentile charts, not these categories.
How do I calculate BMI in kg and cm?
Divide your weight in kilograms by your height in metres, squared — so convert centimetres to metres first (170 cm = 1.70 m). For 70 kg at 170 cm: 70 ÷ (1.70 × 1.70) = 24.2. Use the metric tab above to skip the conversion — enter kg and cm directly.
What is a healthy BMI?
The WHO considers 18.5 to 24.9 healthy for most adults. Many health bodies lower the overweight threshold to 23 for people of South or East Asian descent.
Is BMI accurate for athletes?
No. BMI cannot distinguish muscle from fat, so muscular people are often classed as overweight despite low body fat. Waist measurement or body fat percentage is more useful for them.
Can I use this for my child?
No. Children and teenagers need BMI-for-age percentile charts specific to their age and sex — ask a paediatrician or use a CDC/WHO growth chart.