Enter your height in centimeters and weight in kilograms — get your BMI instantly.
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Most of the world runs on metric, and BMI is genuinely simpler with it. The formula is: weight (kg) ÷ height (m)². So if you’re 170 cm (1.70 m) and 70 kg, that’s 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2. Done. No feet-and-inches gymnastics, no pound conversions.
Why does this matter? Because when you calculate BMI in metric, the numbers behave in an intuitive way. Every 10 cm of extra height requires roughly 6–7 kg more weight to keep the same BMI. A 180 cm adult at the top of the healthy range (BMI 24.9) weighs 80.7 kg; a 170 cm adult at the same BMI weighs 72 kg. That linear-ish relationship is easy to keep in your head, which is one reason nutritionists and clinicians outside the US default to kilograms and centimeters.
The tool above is locked to metric so you don’t have to hunt for the toggle. Enter your height in cm using either the number input or the slider, do the same for weight in kg, and the result updates live. You’ll see your BMI number, which category it falls into (WHO thresholds: healthy 18.5–24.9, overweight 25–29.9, obesity 30+), and the healthy weight range in kilograms for your exact height.
A few metric BMI reference points worth committing to memory: a healthy adult at 160 cm weighs between 47.4 and 63.7 kg. At 170 cm, that range is 53.5 to 71.9 kg. At 180 cm, it’s 60 to 80.6 kg. And at 190 cm, it’s 66.8 to 89.7 kg. Anywhere inside those brackets is statistically fine.
If you’d prefer imperial, we have a matching BMI Calculator in lbs and inches. For men specifically, try our male BMI calculator; for women, the female version. All of them run entirely in your browser — nothing gets uploaded, nothing gets logged.
BMI = weight (kg) ÷ height (m)². If your height is in centimeters, divide by 100 first to get meters, then square it. Example: 65 kg ÷ (1.68 × 1.68) = 23.0.
A healthy BMI is 18.5 to 24.9, regardless of units. The kilogram range for a healthy BMI depends on your height — at 170 cm, that’s roughly 53.5 to 71.9 kg. The calculator above shows the exact kg range for your height.
Divide your height in cm by 100 to convert to meters. Multiply that number by itself. Divide your weight in kg by the result. That’s your BMI. Example: 175 cm becomes 1.75 m; squared is 3.0625; divide 72 kg by 3.0625 = BMI 23.5.
The number is identical — the formula is dimensionally the same. Metric is just easier to compute in your head and easier to teach. Imperial requires a fudge factor of 703 (BMI = 703 × lbs ÷ inches²), which is not intuitive at all.
A healthy BMI (18.5 to 24.9) at 165 cm corresponds to 50.4 to 67.8 kg. The calculator above will give you the exact numbers for any height in cm.
We wrote a plain-English guide that covers the history, the limits, and what to actually do about your number.
Read the BMI guide →