BMI Prime: Reading Your BMI Against 25
BMI Prime repackages BMI so the healthy-range boundary is always 1.0. This post shows the maths and the limits of the idea.
What is the BMI Prime Calculator?
BMI Prime divides your BMI by 25, the top of the usual healthy range, so 1.0 marks that boundary in a single number. Below 1.0 sits under the boundary and above 1.0 sits over it. It is the same information as BMI in a different form, and it carries the same limits for very muscular or older adults.
How to use it
- Enter your weight in kilograms.
- Enter your height in centimetres.
- Click Calculate BMI Prime.
Worked example
70 kg at 170 cm gives a BMI of 24.22 and a BMI Prime of 0.97.
What does a BMI Prime of 1.2 mean?
It means the BMI is 20 percent above 25, since 1.2 times 25 is 30. The number is easy to read but no more precise than BMI itself.
Frequently asked questions
Why divide by 25?
25 is the top of the commonly used healthy BMI range, so dividing by it puts that boundary at exactly 1.0.
Does BMI Prime suit athletes?
No better than BMI does; muscle can push both figures up without extra body fat.