The metric shortcut most people want
If your height is in centimetres, move the decimal two places to turn it
into metres. Then divide weight by height squared. For example, 173 cm is
1.73 m, so 72 kg at 173 cm becomes 72 divided by 1.73 twice, which gives a
BMI of about 24.1. The calculator does this instantly, but seeing the
shortcut helps you sanity-check the result.
Common kg/cm examples
Example BMI calculations using kilograms and centimetres | Height | Weight | BMI | Adult category |
| 160 cm | 60 kg | 23.4 | Healthy weight |
| 170 cm | 75 kg | 26.0 | Overweight |
| 180 cm | 80 kg | 24.7 | Healthy weight |
How much does 5 kg change BMI?
Approximate BMI change from five kilograms at different heights | Height | BMI change per 5 kg | Why it helps |
| 155 cm | About 2.1 BMI points | Small weight changes move BMI more at shorter heights. |
| 170 cm | About 1.7 BMI points | A 5 kg change can still shift category near a boundary. |
| 185 cm | About 1.5 BMI points | Taller bodies need more kg for the same BMI movement. |
Switching between metric and US units
The unit toggle lets you move between kilograms/centimetres and
pounds/feet/inches instantly. The result is identical either way for the
same body - only the input units differ. This is handy if you know your
weight in one system and your height in another.
Interpreting your BMI
BMI in kg uses the same adult categories as the main calculator; the only
difference is the input system. Treat the category as a screening signal,
then add context: waist size, training, age, pregnancy status, medications,
and any recent unintentional weight change. If you mainly came here because
you measure in kg, this page should give you the practical metric view
without making you read another generic BMI guide.
Frequently asked questions
Can I calculate BMI in kg and cm?
Yes. Switch the toggle to metric units and enter your height in centimetres and your weight in kilograms. The calculator converts your height to metres internally and returns your BMI rounded to one decimal place, with the matching adult category.
How do you calculate BMI?
In metric units, BMI = weight in kilograms ÷ (height in metres × height in metres). In US units, BMI = (weight in pounds ÷ (height in inches × height in inches)) × 703. The calculator above does this for you and rounds the result to one decimal place.
What's my BMI, and how do I read the number?
Your BMI is a single number that maps to a category: below 18.5 is underweight, 18.5-24.9 is the healthy weight range, 25.0-29.9 is overweight, and 30.0 or above falls into the obesity range. The number is a screening signal, not a verdict on your health, so use it as one input among many.
Is a BMI calculator accurate?
A BMI calculator accurately reports the BMI number for the height and weight you enter. As a health measure, BMI is a useful screening tool for populations, but it has limits for individuals: it does not separate muscle from fat and does not account for where fat is stored. It is best used as a quick check, not a diagnosis.
Is my height and weight kept private?
Yes. The calculator runs entirely in your browser using JavaScript. Your height, weight, age, and any other input are never sent to a server or stored by us, so your measurements stay on your device.