Your BMI
24.7
Normal weight
Healthy weight range
59.9–81
kg for your height
BMI prime
0.99
ratio to upper normal limit (1.0)
Where you fall on the scale
Ponderal index
13.7
kg/m³ — better for very tall or short people
Normal BMI band
18.5–24.9
WHO healthy range for adults
How the BMI Calculator Works
The formula
Body mass index divides your weight in kilograms by the square of your height in meters: BMI = kg / m². If you enter imperial units, they are converted first, so the result is identical either way. The World Health Organization then classifies the number: under 18.5 is underweight, 18.5–24.9 is the normal range, 25–29.9 is overweight, and 30 or above falls into the three obesity classes.
Healthy weight range
The healthy weight range shown is simply the weight that would put your BMI between 18.5 and 24.9 at your current height. It is a population-level guideline rather than a personal target — where you feel and perform best within (or near) that range depends on your build and muscle mass.
Know the limits
BMI is a screening tool, not a body composition measurement. It cannot tell muscle from fat, so a muscular athlete may read as overweight while someone with little muscle can read normal despite high body fat. BMI prime and the ponderal index shown alongside give extra context, but for a real assessment of body composition, look at measurements like waist circumference or a body fat estimate.
Frequently asked questions
What is BMI and how is it calculated?
Body mass index (BMI) is your weight in kilograms divided by the square of your height in meters: BMI = kg / m². It is a quick screening tool that classifies adults as underweight, normal weight, overweight, or obese using the WHO cut-off points.
What is a healthy BMI?
For adults, the World Health Organization considers a BMI between 18.5 and 24.9 to be the normal (healthy) range. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above falls into the obesity classes.
What are the limitations of BMI?
BMI does not distinguish muscle from fat, so muscular athletes can be classified as overweight while people with low muscle mass can have a normal BMI despite excess body fat. It also doesn't account for age, sex, or fat distribution. Treat it as a screening starting point, not a diagnosis.
What is BMI prime?
BMI prime is your BMI divided by 25, the upper limit of the normal range. A BMI prime below 1.0 means you are within or under the normal range; above 1.0 shows how far over the limit you are (for example, 1.10 is 10% over).
What is the ponderal index?
The ponderal index (PI) is weight divided by height cubed (kg / m³). Because it cubes height rather than squaring it, it gives more reliable readings for very tall or very short people. A typical healthy PI is roughly 11 to 15.