BMI Calculator
Enter your height and weight to get your body mass index, its WHO class and the healthy weight range for your height. A reference figure, not a medical assessment.
WHO adult BMI classes
For adults. A reference figure, not a medical assessment. Nothing you enter is saved.
How to use the BMI Calculator
- Enter your height in centimetres and your weight in kilograms. The result updates as you type.
- Read your BMI to one decimal place and its World Health Organization class, with a bar showing where you sit.
- Check the healthy weight range for your height and how many kilograms separate you from it.
The WHO classes this page uses
Weight in kilograms is divided by height in metres squared. The World Health Organization classes adults as underweight below 18.5, normal weight from 18.5 to under 25, pre-obesity from 25 to under 30, and obesity class I, II and III from 30, 35 and 40. An exact 25.0 falls on the pre-obesity side. Several Asian guidelines, including Koreaโs, draw the overweight line at 23.
| WHO class | BMI |
|---|---|
| Underweight | under 18.5 |
| Normal weight | 18.5 โ 24.9 |
| Pre-obesity (overweight) | 25.0 โ 29.9 |
| Obesity class I | 30.0 โ 34.9 |
| Obesity class II | 35.0 โ 39.9 |
| Obesity class III | 40 and above |
Source: WHO adult BMI classification.
What the normal band means at your height
Because the index divides by height squared, the weight range for a band shifts upward with every few centimetres. The table gives the weights that land inside 18.5 to 25 on this page.
| Height | Weight for a BMI of 18.5 to under 25 |
|---|---|
| 155 cm | 44.5 - 60.0 kg |
| 160 cm | 47.4 - 63.9 kg |
| 165 cm | 50.4 - 68.0 kg |
| 170 cm | 53.5 - 72.2 kg |
| 175 cm | 56.7 - 76.5 kg |
| 180 cm | 60.0 - 80.9 kg |
Rounded to 0.1 kg inside the band.
Frequently asked questions
What do the BMI ranges mean?
Under 18.5 is underweight, 18.5 to under 25 normal weight, 25 to under 30 pre-obesity, and 30, 35 and 40 start obesity classes I, II and III. Some countries apply lower thresholds for Asian populations.
Is this a diagnosis?
No. BMI does not distinguish muscle from fat and says nothing about where weight is carried, so athletes and older adults are often misclassified. Speak to a healthcare professional for an actual assessment.
What is the BMI for 170 cm and 65 kg?
22.5, inside the normal band. It is 65 divided by 1.7 squared, or 2.89, and the page rounds to one decimal place.
Does it break overweight into obesity classes?
Yes. Results above 25 are labelled pre-obesity, then obesity class I from 30, class II from 35 and class III from 40, following the WHO adult classification.
What is a healthy weight for my height?
The calculator shows the weight range that gives a BMI from 18.5 to under 25 at your height, and how many kilograms you would need to lose or gain to reach it.