NASM'S BMI CALCULATOR

How to calculate bmi

Understanding your Body Mass Index (BMI) is simple when you have your weight and height at hand. Here's how you can work it out:

In metric measurements:

BMI = weight in kilograms ÷ (height in meters squared)

For imperial measurements:

BMI = 703 × weight in pounds ÷ (height in inches squared)

Let's use Mary as an example:

Mary weighs 160 lb (approximately 72.57 kg) and is 5 ft 7 in. (which is 67 inches or 1.70 meters). Plugging these values into either formula, we find that Mary's BMI is 25.1.

bmi chart

For adults, BMI is grouped into specific categories that reflect a range of weight statuses, from "very severely underweight" to "very severely obese". These classifications are rooted in typical data from the general population. The chart provided (Table 1) is tailored to the American population, but it's worth noting that variations exist based on regional standards in different countries.

Is BMI calculated differently for males and females?

The Body Mass Index (BMI) is a universal tool used to categorize weight in adults, irrespective of gender. Interestingly, given the inherent physiological differences between men and women, women generally possess a slightly elevated body fat percentage at an identical BMI. This distinction is where body fat scales can offer enhanced insights into the unique body compositions of both genders. Refer to the table for a breakdown of body fat percentages delineated by biological sex. Now, BMI works pretty well if your height is around the average. But if you're notably shorter or taller than most, it might not be as accurate. In simpler terms, shorter folks might find BMI paints them as having more body fat than they do, while taller individuals might find the opposite.