BMI from kg and cm
Most of the world measures weight in kilograms and height in centimetres,
so this page starts in metric. The calculator converts your height to
metres behind the scenes and applies the standard formula. You do not need
to do any conversion yourself.
The metric BMI formula
BMI = weight (kg) ÷ [height (m) × height (m)]. For example, 72 kg at 173 cm
becomes 72 ÷ (1.73 × 1.73) ≈ 24.1. Enter your numbers above and the result
appears rounded to one decimal place, along with the matching adult
category.
Adult BMI categories
Adult BMI categories for ages 20 and older | Category | BMI range |
| Underweight | Below 18.5 |
| Healthy Weight | 18.5 - 24.9 |
| Overweight | 25.0 - 29.9 |
| Obesity | 30.0 and above |
| Class 1 Obesity | 30.0 - 34.9 |
| Class 2 Obesity | 35.0 - 39.9 |
| Class 3 Obesity | 40.0 and above |
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
Your category is a screening signal rather than a diagnosis. BMI in kg uses
the same scale as everywhere else and shares the same limits: it cannot
separate muscle from fat or show fat distribution. For personal questions,
check with a healthcare provider.
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.